Archive for 2017

Coaxial Cable Repair Kit Now Available

GM has implemented a new service strategy using universal coaxial cable repair kits to repair cables used for high frequency signals, such as cellular (OnStar), satellite radio (XM), GPS (navigation, and the AM/FM signal, on 2006-2018 GM models. There are eight individual kits available.


Coaxial cable is used to protect the signal from external interference. It has an inner conductor surrounded by an insulating layer that is surrounded by a conducting shield.


Original Equipment Manufacturer (OEM) replacement cables should be used when the exact cable is available and replaceable. In cases where this is not possible, the service kits should be used. Repairs may require the use of one or more kits.


Service Strategy


When making coaxial cable repairs, it’s not necessary to remove the old coaxial cable from the vehicle. Using the cable repair kits, a new service cable should be routed in the vehicle from point A to point B. Secure the cables using tie straps, electrical tape, or clips with foam tape to prevent possible rattling.


It may be necessary to combine various lengths of cable to create the needed length. Extra cable can be coiled around itself. However, do not bend the cable in more than a 2-inch radius to prevent damage to the cable.


The service cables have a 1-way universal connector on each end. If a different end is needed, use a jumper to connect from the 1-way connector to the proper connector.


If an in-vehicle connector is damaged, it may be possible to replace it with a new service connector housing from one of the service kits. Kits include non-keyed water blue connectors for 1-way and 2-way styles. The 3-way connectors are color coded. If it’s not possible to replace only a connector, run a cable and bypass the non-replaceable connector.


Repair Kits


The following kits are available for service.


  1. Communication Interface (OnStar) Module Antenna Cable Kit – replaces the cables for carrying a cellular signal or a combined cellular and GPS signal. It is also referred to as the long run cellular kit. It includes four different RG58LL cables in lengths of 18 inches (Fig. 1, A), 3.5 feet (Fig. 1, B), 5 feet (Fig. 1, C) and 7 feet (Fig. 1, D).


Fig. 1


  1. Digital Radio (XM) and Vehicle Locator (GPS) Antenna Coaxial Cable Kit – replaces RG316 or RG174 satellite radio and GPS cables. It is also referred to as the long run XM/GPS kit. It includes three different RG174 cables in lengths of 3.5 feet (Fig. 2, A), 5 feet (Fig. 2, B) and 7 feet (Fig. 2, C).


Fig. 2


  1. Digital Radio (XM), Mobile Telephone (OnStar) and Vehicle Locator (GPS) Antenna Coaxial Cable Kit – used to repair a connector or in conjunction with the long run kits to change the connector ends. It is also referred to as the connections kit. It includes different connectors, housings and jumpers to mate into the connector housings. (Fig. 3)


Fig. 3


  1. Digital Radio (XM), Mobile Telephone (OnStar) and Vehicle Locator (GPS) Antenna Cable – includes one 90 degree adapter cable to be used with any of the long length cable kits. (Fig. 4) Available individually or as part of the Digital Radio (XM), Mobile Telephone (OnStar) and Vehicle Locator (GPS) Antenna Coaxial Cable Kit.


Fig. 4


  1. Communication Interface (OnStar) Module Antenna Cable Kit – includes a 4-inch jumper for the mini-UHF connector used on several OnStar modules before the 2011 model year. (Fig. 5)


Fig. 5


  1. AM/FM Radio Antenna Cable Kit – used to replace the cables for carrying an AM/FM signal. These cables are used to connect between the radio and any AM/FM antenna (mast, glass antenna amplifier, glass antenna module, or roof mounted antenna base). It includes three different RG59 cables in lengths of 3.5 feet (Fig. 6, #1), 5 feet (Fig. 6, #2), and 7 feet (Fig. 6, #3).


Fig. 6


  1. AM/FM/XM Connector Antenna Jumper with Dual Connector – used to connect a single AM/FM coaxial cable to an existing dual connector at the antenna. It includes one 4 inch universal antenna connector adaptor and a universal dual connector body. (Fig. 7) Re-use the factory dual connector body (Fig. 8), or use the water blue universal connector body if the original is not serviceable.


Fig. 7


Fig. 8


  1. AM/FM Radio Antenna Jumper Cable with Tyco Right-Angle Connector – used on 2006-2010 radios; all Acadia, Captiva, Enclave, Express, Savana, and Traverse models with radio RPOs UG4, UGU, UUI, UHU, UJL, UGY, UGX, UI6, UI4, UUI, UI2, UI5, UI7, or UI8; and can be used on additional models with the same connection. It includes a 90-degree adapter cable to be used with any of the long length cable kits. (Fig. 9)


Fig. 9


For additional information and part numbers, refer to Bulletin #17-NA-346.


– Thanks to Matt Bunting


EV Battery Service and Depowering Tool Software Update

A software update for the EL-50332 EV Battery Service and Depowering Tool (Fig. 10) is now available through the Service Workbench selection of “Essential Tools – Software Updates” in GM GlobalConnect. The update (EL-50332-370H) includes programming enhancements to increase the upper voltage threshold for the Bolt EV and CT6 battery packs and also adds three global applications to the vehicle menu selections.


Fig. 10


voltage level of a replacement battery section to the existing battery sections following a service event on 2011-2018 Volt; 2014 ELR; 2014-2016 Spark EV; 2017-2018 Bolt EV and CT6 PLUG-IN models.


Software Updates


The EL-50332 tool requires periodic software updates, which are available on the GM Dealer Equipment Website (U.S.). GM dealerships can download the updates free of charge by going through GM GlobalConnect > Service Workbench > GM Essential Tools – Software Updates.


In Canada, go to the Service Department page in GM GlobalConnect and select “GM Special Tools & Equipment – Software Updates” located under the Applications section.


To update the EL-50332 tool when software updates are available, use the Update function found under the Utility menu on the tool. Insert a USB-style flash drive with the updated software into the USB-A port. When performing an update, the tool will first check the inserted USB drive. Next, the version information of the currently loaded software and the new version information found on the USB drive will be displayed on the screen.


The current software version on the tool also can be checked by going to the Tool Info menu and selecting the Version utility. Tool information available in the Version utility includes the software version, EEPROM, version date, tool serial number, and build number. Use the arrow keys to scroll between the screens of version information.


TIP: To view the EL-50322 Instruction Manual, go to the website and select the Software Downloads link. The manual is listed under Support Documents for the EL-50322 tool. (Fig. 11)


Fig. 11


Battery Section Balancing


The EL-50332 tool charges and discharges the replacement battery section through a direct connection to the replacement battery section positive and negative terminals. The replacement section is charged or discharged, as required, based on measured cell group voltage data.


Prior to servicing any High Voltage component or connection, always perform the High Voltage Disabling procedure. Personal Protection Equipment (PPE) and proper procedures must be followed.


The EL-50332 tool includes a universal fuse box, an interface module and a number of cables. Before beginning the balance procedure, make sure all the external EL-50332 components and cables are properly connected. Refer to the Hybrid/EV Battery Cell Balancing procedure in the appropriate Service Information for complete instructions on connecting the EL-50332 tool. (Fig. 12)


Fig. 12


If any codes appear when starting up the tool, check the following:

  • Make sure the USB memory stick is fully inserted into the tool.
  • Do not hook the machine to the battery section until instructed to do so by the tool.
  • Update the tool software to the latest version available.


Depending on the charge condition of the battery pack and the section being balanced, the balancing process can take up to four hours to perform. A warranty code and pack voltage current data will be displayed at the conclusion of the balancing event. An audible tone will sound at the end of balancing or if there is a fault condition.


– Thanks to Chuck Berecz


2018 Buick Enclave Service Tips

These service procedures on the new 2018 Enclave differ from the previous model year vehicle. Refer to the appropriate Service Information for more details.


Outside Rearview Mirror Fasteners: The fasteners are bolts through the door sheet metal; there are no studs on the mirror base. (Fig. 13)


Fig. 13


Rear Door Upper Reveal Moldings: “Football” clips on the run channel/glass assembly hold the molding in place. Use a trim stick and twist (do not pull straight off) to release the molding or the clips will break. The aluminum upper molding will bend easily if caution is not used.


Roof Rack/Ditch Moldings: Studs through the roof hold on the roof rack. The headliner must be removed to service. Ditch moldings (Fig. 14) are now clipped in and it may be difficult to prevent damaging them during removal. They may require replacement when servicing.


Fig. 14


Front Door Trim Removal: Two screws located at the bottom of the door trim must be removed in order to remove the door trim. (Fig. 15)


Fig. 15


Headliner Material: The robust headliner material is easy to remove by tilting the headliner down on the right-hand side and removing it through the liftgate opening.


Headliner Removal: Remove 1/4 trim on the right-hand side and remove the rear air duct (Fig. 16) to prevent the air duct from breaking the integrated duct work in the headliner.


Fig. 16


Overhead Console: Use care when pulling down the garage door opener (roof console) bezel to prevent damage to the wiring harness connector. Since the harness is glued to the headliner, carefully removing the bezel will prevent damage to the connector. (Fig. 17)


Fig. 17


One-Piece Glovebox: The one-piece glovebox incorporated into the knee bolster (Fig. 18) means that the console needs to be removed to service the glovebox.


Fig. 18


Steering Wheel Shroud: The steering wheel shroud is incorporated into the cluster trim as a one-piece unit that requires removal of the steering wheel to service.


Driver’s Airbag: Removing the driver’s airbag requires turning the wheel left, right, and then bottom side up to release the spring fasteners (Fig. 19, #3) in order to remove the airbag.


Fig. 19


– Thanks to Sherman Dixon and Steve Bruder


Remanufactured V6 Engine Misfire

An engine misfire may be found on some GM remanufactured 2.8L, 3.0L and 3.6L High Feature V6 engines immediately after installing the engine. The misfire is usually limited to one bank or one cylinder, often cylinder 5 or 6.


The 2.8L engine (RPO LPI, LAU), 3.0L engine (RPOs LFI, LFW) and 3.6L engine (RPOs LY7, LLT, LFY, LFX) are available on 2007-2009 G6; 2007-2010 Aura, Outlook; 2007-2011 STS; 2007-2012 Malibu; 2007-2016 Allure (Canada only), CTS, SRX; 2007-2017 Enclave, LaCrosse, Equinox, Acadia; 2008-2009 G8, Torrent; 2008-2010 Vue; 2009-2017 Traverse; 2010-2015 Camaro; 2010-2016 Terrain; 2012-2018 Impala; 2013-2015 ATS; and 2015-2016 Colorado, Canyon models.


If the misfire condition is present, it may be caused by the wrong camshaft installed in the engine at the remanufacturer’s facility.


Inspect the camshafts to ensure the correct camshaft is installed in each intake and exhaust position by comparing the ring strategy to either the engine that was removed (recommended) or to the charts included in #PIP5528.


Ring strategy camshaft identification is a series of rings along the camshaft that are either simply cast on the camshaft or machined down. There are five rings on each camshaft, which can be identified by the order in which the cast rings (Fig. 20, #1) or machined rings (Fig. 20, #2) are on the camshaft.


Fig. 20


If the wrong camshaft is installed, either replace the camshaft with the same one from the original engine if undamaged or with a new camshaft. It is not necessary to replace the engine.


– Thanks to Aron Wilson

Pop Sound from Front Suspension Area while Making Turns

Some 2015-2018 Escalade, Silverado, Suburban, Tahoe, Sierra and Yukon models may have a clicking, popping, or cracking sound coming from the front suspension or front frame area while the vehicle is making turns. The sound also may be felt in the footwell area.


The sound may be caused by either insufficient torque of the front frame crossmember or lower control arm bolts.


Frame Crossmember


To correct the sound coming from front frame crossmember, loosen and re-torque the four crossmember bolts (Fig. 21) to 70 Nm (52 lb.-ft.) on the first pass, followed by 110 degrees on the final pass.


Fig. 21


Front Lower Control Arm


To correct the sound coming from the front lower control arm, loosen and re-torque the four lower control arm bolts (Fig. 22) to 175 Nm (129 lb.-ft.).


TIP: If the front lower control arms nuts and washers are removed, the directional washers must be installed in the same direction as they were removed.


Fig. 22


When performing the service procedure, document the before and after torque readings on the repair order.


– Thanks to James Will

Service Know-How

10217.11V – Emerging Issues

November 9, 2017


The latest service topics from Brand Quality and Engineering are reviewed, including a review of Warranty Parts Center shipping safety guidelines and an introduction to the new Dealer Case Management system. (Fig. 23)


To view Emerging Issues seminars:

  • Log into
  • Enter Emerging Issues in the Search box.
  • Select the desired Emerging Issues seminar course title.
  • Click the Launch button.


Fig 23

All-New 2018 Buick Enclave

The 2018 Enclave, Buick’s all-new seven passenger midsize luxury SUV, features a longer wheelbase than the previous generation with a body structure built for safety, strength and mass efficiency. The standard 3.6L V6 engine with Stop/Start technology is paired with an efficient 9-speed automatic transmission. Plus, there are 17 radar, camera and ultrasonic sensors, when fully equipped, that provide a wealth of data for the numerous safety and collision avoidance features.


New Model, New Technology


The 2018 Enclave is now available in a new Avenir model, which is Buick’s new luxury sub-brand that offers unique styling cues and an extensive list of premium features. (Fig. 1)


Fig. 1


The new styling of the Enclave showcases a lower roofline and sharper windshield angle than the model it replaces. It includes Buick’s traditional QuietTuning sound-blocking features, yet with a new active noise cancellation system.


Also offering additional comfort for passengers is the new available air ionizer that eliminates odors and provides enhanced air quality. The air ionizer works by producing negatively charged particles that attract air-born contaminants and break down their structure, cleaning the cabin air. The ionizer doesn’t require any maintenance, but the traditional cabin filter should be serviced regularly. To turn the ionizer on or off, go to Settings > Vehicle > Climate and Air Quality.


High Feature V6


The High Feature 3.6L V6 engine (RPO LFY) uses variable valve timing (VVT) and direct injection (DI) to produce 310 horsepower and 266 lb.-ft. of torque. (Fig. 2) It uses dexos1 SAE 5W-30 viscosity grade engine oil.


Fig. 2


The fuel efficient Stop/Start technology on the engine is similar to the Stop/Start system found on other GM vehicles. An advanced algorithm determines when driving conditions are optimal to turn off the engine. The system monitors vehicle speed, climate control system operation and other conditions. The advanced system recognizes certain driving maneuvers, such as backing into a garage or parking lot situations, to better determine whether or not the vehicle needs to operate the stop/start function. Unique Stop/Start system components include a tandem-solenoid starter, DC-DC module that maintains voltage during a stop/start event, an electronically-controlled accumulator that retains transmission fluid pressure, and an engine mount system that dampens vibrations.


9-Speed Transmission


The 9T65 (RPO M3W) 9-speed, transverse-mounted, electronically-controlled automatic transmission consists primarily of a 4-element torque converter, a compound planetary gear set, friction and mechanical clutch assemblies, and a hydraulic pressurization and control system. (Fig. 3) The Transmission Control Module (TCM) is a standalone unit mounted on a bracket near the transmission. Use DEXRON®-VI Transmission Fluid in the 9T65.


Fig. 3


Selecting a gear is done with the shift-by-wire Electronic Precision Shift (EPS) gear selector, which eliminates the mechanical connection to the transmission. (Fig. 4) The automatic transmission shift pattern — Park, Reverse, Neutral, and Drive, and Manual positions — is displayed on top of the shift lever. The shift lever position is determined by two internal sensors that each transmit an X and Y coordinate signal. All four signal circuits are inputs to the Chassis Control Module. The selected gear position illuminates in red on the shift lever.


Fig. 4


The shift lever includes a Shift Interlock Button on the side of the lever that must be pressed to shift out of Park or into Reverse as well as a Park Button on top of the lever that must be pressed to shift the transmission into Park.


Switchable All-Wheel Drive


Available intelligent All-Wheel Drive (AWD) with an active twin-clutch rear differential — independently controlling torque to each rear wheel — and Buick’s first switchable AWD system improve control and efficiency. Switchable AWD allows the driver to switch between front-wheel drive and AWD when road conditions change. (Fig. 5) In front-wheel drive, the system disconnects virtually all of the AWD components from the drivetrain to save fuel and reduce emissions.


Fig. 5


In addition, the Enclave comes standard with the driver-controllable Traction Select system, which offers choices for different driving conditions, and changes the throttle response and other calibrations for the selected driving mode.


The Driver Mode Control also provides additional driver control with Sport and Tow/Haul modes. The system simultaneously changes the software calibration of various sub-systems, including the suspension, steering, and powertrain settings. On vehicles with Sport and Tow/Haul modes, there is only one selectable button (Tow/Haul), which engages both the Sport features as well as the Tow/Haul features when enabled.


Infotainment System


The infotainment system on the Enclave includes an 8-inch (203 mm) diagonal color touchscreen. (Fig. 6) The standard system (RPO IO5) features gesture control (use simple gestures such as tap, drag and swipe to navigate through menus and screens), in-vehicle apps via Shop, Apple CarPlay™ and Android Auto™ compatibility, and natural language voice recognition. The available system (RPO IO6) with embedded navigation offers easy-to-understand turn-by-turn directions. Navigation features can be accessed using the touchscreen, voice command or within the instrument cluster using the steering wheel-mounted buttons.


Fig. 6


SmartSlide Seating


The SmartSlide 2nd-row seat on the passenger side of the vehicle can be slid and angled forward using the handle on the side of the seatback, allowing passengers easy access to the 3rd-row seats on the curb side of the vehicle. The seat slides and tilts forward even when a forward-facing child restraint is installed using the LATCH system. Remove a rear-facing child restraint before moving the seat for 3rd-row entry or exit.


Safety Features


The Driver Assistance Systems — an expanded range of radar- and camera-based active safety technologies — are designed to enhance driver awareness and aid in reducing potential collision situations.


Some of the available Driver Assistance features include:

  • Adaptive Cruise Control
  • Forward Automatic Braking
  • Forward Collision Alert with Following Distance Indicator
  • Front Pedestrian Braking
  • Lane Keep Assist with Lane Departure Warning
  • Lane Change Alert with Side Blind Zone Alert
  • Rear Cross Traffic Alert
  • Rear Parking Assist
  • IntelliBeam high-beam headlamp control
  • Safety Alert Seat
  • Surround Vision camera system


Power Liftgate


The available hands-free power programmable liftgate can be opened and closed by simply using a kicking motion under the driver’s side of the rear bumper, just left of center. It also features a Buick Tri-Shield logo that is projected onto the ground by an LED lamp under the rear bumper to indicate the hands-free sensor location. (Fig. 7) The key fob must be within 10 feet (3 m) of the back of the vehicle to activate the projected logo. The projected logo may not be visible in all conditions, such as on snow-covered ground or on a bright, sunny day.


Fig. 7


Spare Tire Access


To access the spare tire, the cargo management system below the rear cargo floor must be removed. (Fig. 8) Remove the four wing nuts and lift up on the handles on both sides to remove the cargo management system. The storage bin can be placed on the lowered third row seats while accessing the spare tire.


Fig. 8


Special Tools


The following special service tools have been released for the 2018 Enclave:


DT-48022 Bushing Installer DT-51834 Seal Installer, RH Input & Pinion Cassette DT-51835 Seal Installer, LH Input & IDS Cassette EN-51332 Fuel Line Release Tool


For additional information on the new 2018 Enclave, refer to Bulletin #17-NA-285.


– Thanks to Sherman Dixon and Steve Bruder


Intake Rocker Arm Oil Control Valve Components

Some 2014-2015 Impala (VIN 1) and Malibu models equipped with the 2.5L engine (RPO LKW) may have several driveability conditions, such as a surge, rough idle, or misfire. The engine may misfire on cylinders 1 and 2 or cylinders 3 and 4. DTCs P0101 (MAF Sensor Performance), P0106 (MAP Sensor Performance), P0171 (Fuel Trim System Lean) or P0300 (Engine Misfire Detected) also may be set.


If these conditions are found, follow the appropriate diagnostic procedures in the Service Information. If the concern is not resolved, inspect the intake rocker arm oil control valve for missing components. (Fig. 9)


Fig. 9


If any intake rocker arm oil control valve components are missing, replace the intake rocker arm oil control valve and the camshaft cover. The camshaft cover must be replaced because some components may have become lodged in the camshaft cover oil passages.


If the intake rocker arm oil control valve is not missing any components (Fig. 10), only replace the intake rocker arm oil control valve.


Fig. 10


– Thanks to David Rutkowski

Forward Collision System Reduced Message

A Forward Collision System Reduced message (Fig. 11) may appear on the Driver Information Center (DIC) when the vehicle is started on 2016-2018 CT6, Escalade, Malibu, Volt; 2017-2018 XT5, Bolt EV, Silverado, Suburban, Tahoe, Acadia, Sierra, Yukon; 2018 Enclave, Equinox, and Traverse models equipped with Low Speed Forward Automatic Braking (RPO UHY). On some 2016 models, the DIC message displayed may be Automatic Collision Prep Reduced.


Fig. 11


When driving in a forward gear, if the Forward Automatic Braking system detects another vehicle ahead in the path that the vehicle traveling and in the same direction, it can provide a boost to braking or automatically brake the vehicle to help avoid or lessen the severity of a collision. Depending on the situation, the vehicle may automatically brake moderately or hard. The system works when driving in a forward gear between 5 mph (8 km/h) and 50 mph (80 km/h) or, on vehicles with Adaptive Cruise Control, above 2 mph (4 km/h). It can detect vehicles up to approximately 197 ft. (60 m).


There are three possible settings for the Forward Automatic Braking system:

  • Off
  • Alert
  • Alert and Brake


The Forward Collision System Reduced DIC message will be displayed when the Forward Automatic Braking system has been set to the “Alert” setting in the Vehicle Settings on the infotainment system.


The Alert setting disables most automatic braking functions, providing reduced operation. This is normal when the system has been set to “Alert.”


If the system is set to “Alert and Brake,” (Fig. 12) the DIC message will no longer by displayed when the vehicle is started.


Fig. 12


– Thanks to James Will

UPDATE: Loose Charge Air Cooler Ductwork

Loose connections of the charge air cooler ductwork on some 2017-2018 Silverado and Sierra models equipped with the 6.6L Duramax diesel engine (RPO L5P) may result in an illuminated Check Engine light. DTCs P0101, P0299, P0712, P11CC, P11DC, P2002, P2463, P2627, P2A00, P2459, P22B6, P200C, P200E, P0263, P0266, P0269, P0272, P0275, P0278, P0281 and/or P0284 also may be set.


If any of the DTCs are set, check for loose charge air cooler ductwork at the turbocharger outlet pipe, the charge air cooler inlet pipe, the charge air cooler outlet pipe, and the connection at the intake air flow valve (throttle body). (Fig. 13)


Fig. 13


TIP: The loose ductwork is most likely to become disconnected during engine roll or brake torque. Test for leaks using the smoke test procedure in the Charge Air Cooler Diagnosis document (Service Information document ID. #4282009).


Also check for proper alignment of the charge air cooler pipe bracket and bolt hole. (Fig. 14) The bracket and bolt hole may require realignment after the charge air cooler outlet hose is properly connected to the throttle body.


Fig. 14


If DTC P2463 (DPF Soot Accumulation) was not set and a charge air cooler leak or disconnection was found, after repairing charge air cooler connections, command the Diesel Particulate Filter (DPF) Regeneration Enable with the scan tool before returning the vehicle to the customer.


The DPF Regeneration Enable will put the vehicle in DPF regeneration mode when the customer gets the vehicle, which will delay any emissions diagnostic codes that can be fouled by high soot in the exhaust until the exhaust is cleaned by the vehicle being driven with an on-road DPF regeneration.


– Thanks to John Stempnik

Battery Vent Plug Installation

Absorbed Glass Mat (AGM) and flooded lead acid batteries can produce a number of potentially dangerous gases, which requires that the battery be properly vented on vehicle applications that have the battery installed inside the passenger compartment. The typical maintenance-free battery is completely sealed except for two small vent ports in the side. These vent ports allow the gas that is produced in the battery to escape.


On applications with a single vent tube, the opposing vent opening on the battery cover must be plugged using the vent plug.


Batteries that require venting include a removable vent plug, which can be inserted into the vent port that is opposite of the vent hose that leads to outside the vehicle. The twist-off plug is attached to the positive terminal cap. (Fig. 15)


Fig. 15


Instructions for using the vent plug are included on the battery positive post cover. (Fig. 16) Press fit the vent plug into the battery to ensure proper seating into the vent port. (Fig. 17) Be sure to never plug both vent ports.


Fig. 16


TIP: Some batteries may have vent hose configurations that vent both ports to outside the vehicle, such as the Saturn Ion. These applications do not require a plug.


Fig. 17


– Thanks to John Munsell

Using the TransFlow Transmission Oil Cooler Flush and Flow Test Tool

GM studies indicate that restricted transmission oil flow is detrimental to the life of any automatic transmission. Plugged oil coolers and oil cooler line restrictions cause insufficient transmission lubrication and elevated operating temperatures that can lead to premature transmission failure. Many repeat repair cases can be prevented by following published procedures for transmission oil cooler flushing and flow checking to ensure there is proper flow through the transmission oil cooler.


The DT-45096 (previously J-45096) TransFlow® transmission oil cooler flush and flow test tool (Fig. 1) can be used to flush and flow test the transmission oil cooler and the oil cooler pipes after the transmission has been removed for repairs. The TransFlow tool is designed to measure oil flow capability within the transmission oil cooler and performs a flow rate test meeting GM flow rate specifications. It is a self-contained unit using a 12-volt flow meter, shop air supply and DEXRON VI automatic transmission fluid (ATF).


Fig. 1


The DT-45096 TransFlow tool uses conventional automatic transmission fluid as the cleaning agent. It doesn’t use any detergents, chemical cleaning agents or hot water, so there is no hazardous waste to dispose of.


If the transmission fluid requirement for the vehicle is different than DEXRON VI, flushing the cooler with DEXRON VI is an acceptable service procedure. Very little fluid remains in the cooler after the flush procedure. After performing the flush and flow test, use compressed air to blow the residual transmission fluid out of the oil cooler and lines.


Time allowance for performing the transmission oil cooler flushing and flow checking procedure has been included in the appropriate labor time guide operations since the 1987 model year.


The DT-45096 TransFlow includes:

  • 32 quart (30 liters) supply vessel
  • 34 quart (32 liters) waste oil vessel
  • Air pressure supply fitting
  • Digital flow rate indicator
  • 12V DC power cable
  • Black supply oil hose with quick connect fitting
  • Clear waste oil hose with quick connect fitting


TIP: A new Operation Manual has just been released with updated information along with a new Adapter Application Chart. The new manuals are available under the Support tab for the DT-45096 (previously J-45096) tool at (Fig. 2)


Fig. 2




The TransFlow equipment is connected to the vehicle’s transmission oil cooler lines using the current cooler line adapters. Two adapters are included with the TransFlow. Five other adapters also are available. The most commonly used adapters are the DT-45096-30 (for 6-speed, 8-speed and 10-speed longitudinally-mounted transmissions) (Fig. 3) and DT-45096-50 (for 6-speed and 9-speed transverse-mounted transmissions). (Fig. 4)


Fig. 3


Fig. 4


In the flush mode, air pressure forces clean transmission fluid through the oil cooler and lines, removing dirty oil and blockages. To enhance the cleaning action, the oil is agitated with bursts of air. The cooler is flushed first in the backflush direction, then the normal flow direction. Waste oil is collected in a built-in waste tank.


Flow Test


After flushing, use the digital flow rate indicator in the DT-45096 to perform a flow test. The flow test indicates whether the oil cooler and cooler lines still have restrictions, which must be addressed before the repair is completed.


An electronic flow meter is used to measure the minimum flow capability of the transmission oil cooling system. A digital display indicates the ATF flow rate in gallons per minute (GPM) along with the amount of ATF in the supply vessel, supply vessel ATF temperature, machine cycles and the operating mode.


Insufficient oil flow through the transmission oil cooling system will cause premature transmission failure. The required minimum ATF flow rate reading is directly related to the supply oil temperature. In addition to transmission fluid temperature, minimum flow rates vary depending on whether the oil cooler is made of aluminum or steel.


Refer to the flow rate chart for the oil flow rate specification based on the temperature of the ATF in the supply vessel. The User’s Manual and the Service Information include minimum flow rate charts. Refer to the appropriate Service Information for complete flow rate information for the model and cooling system being tested.


The published flow rates are based on the tool calibrated at 2.0 GPM (7.6L/minute) using ATF at 65° F (18° C) with 90 psi of air pressure. Dealership tools should be calibrated using the same specifications. (Fig. 5) If the tool is set up with higher temperature ATF, then artificially high flow rates could be seen. Remember, the tool is only measuring minimum flow rates. Fluid warmer than room temperature may result in higher self-test readings.


Fig. 5


The entire flushing and flow test procedure takes only 5-8 minutes. The waste tank can be emptied either using a suction hose in the port provided or by draining from the built-in drain fitting at the bottom of the tank. In either case, the waste oil can be disposed of the in the same manner as any other drained transmission fluid.


After the flow test, the following information is displayed:

  • Tested flow rate in GPM
  • Temperature in degrees Fahrenheit
  • Cycle number
  • 7 or 8-digit alpha/numeric flow code. This flow code must be written on the repair order for the warranty claim.


Self-Test Flow Rate


If an oil cooler fails the flow test, repeat the flow test to confirm the condition. If it fails again, disconnect the tool from the cooler lines and run the TransFlow self-test procedure to verify flow is 2.0 GPM (7.6L/minute) or greater using ATF at 65° F (18° C) with a minimum 90 psi of air pressure. The self-test should take no more than two minutes to complete.


TIP: Refer to the Useful Information/Helpful Hints section of the User’s Manual for additional information on the self-test procedure.


If you are having difficulty obtaining the 90 psi of shop air required to run the TransFlow tool:

  • Connect an accurate pressure gauge between the TransFlow air inlet and the shop to verify the pressure going into TransFlow from the shop air supply is at least 90 psi and there are no obstructions in the shop line.
  • Connect TransFlow to an air line that is closer to the service compressor.
  • Check the service compressor’s pressure.
  • Connect to the body shop air line, which may be at a higher pressure.


Transmission Fluid Temperature


The ATF in the supply vessel must be greater than 65° F (18° C). This is the minimum required operating temperature. Below 65° F (18° C), the TransFlow will shut off. Below this temperature, it is difficult to accurately measure the flow of transmission fluid.


– Thanks to Chuck Berecz, Mark Kevnick and Dan Popoff

Tamper-Proof Drive Bit Set for Emissions Components

The Positive Crankcase Ventilation (PCV) system and other components that affect emissions, but do not turn on the Check Engine lamp if there is a malfunction, are required by the Air Resource Board (ARB) to have tamper-proof fasteners to prevent removal or modification. During service, the fasteners are destroyed if they must be removed, and new tamper-proof fasteners must be installed.


Tamper-proof fasteners can be found on 2016-2018 GM models equipped with the following engines:

  • 4L Gas engine (RPO LE2, LV7)
  • 5L Gas engine (RPO LFV, L3A, L3G)
  • 0L Gas engine (RPO LTG)
  • 6L Duramax diesel engine (RPO LGH, LML, L5P)


Tamper-Proof Drive Bits


The GR-6 bits in the Tamper-Proof Drive Bit Set (EN-50956-A) will install a fastener only, making it ARB compliant. The set includes three tamper-proof bits, and replaces the single bit (EN-50956) (Fig. 6) previously released.


Fig. 6


The tamper-proof fasteners were originally used only on diesel engines, but gasoline applications have been added recently. The tamper-proof fasteners are used to attach various emission-related components, such as the oil separator to the valve cover, the oil drain pipe to the front cover on diesel engines, and components in the intake and PCV systems on gasoline engines.


Service Examples


An example of where tamper-proof fasteners are used is the air cleaner outlet duct on a 2017 Spark equipped with the 1.4L gas engine (RPO LV7). The Service Information instructs to remove the air cleaner outlet duct by using a suitable tool to cut a slot in the tamper-resistant PCV bolt heads (1) and remove them with a flat-bladed tool. (Fig. 7) Discard the bolts after removal. Installing a new air cleaner outlet duct with the PCV tube and valves to the engine requires using the EN-50956 tamper-proof drive bit.


Fig. 7


On 6.6L Duramax diesel engines, a tamper-proof fastener can be found on the PCV oil separator. (Fig. 8)


Fig. 8


– Thanks to Chuck Berecz and Michael Adamczyk


Diagnosing the Selective Catalyst Reduction System

The Check Engine MIL may be illuminated and DTC P20EE (NOx Catalyst Efficiency Below Threshold) may be set on some 2017-2018 Silverado and Sierra models equipped with the 6.6L Duramax diesel engine (RPO L5P). There may be several reasons why DTC P20EE has set, even when the Selective Catalyst Reduction (SCR) system is functioning properly.


The SCR system reduces oxides of nitrogen (NOx) emissions by injecting a metered amount of Diesel Exhaust Fluid (DEF), or reductant, into the exhaust gas stream entering the SCR. Within the Selective Catalytic Reduction Catalyst, the reductant reacts with the NOx to form nitrogen, carbon dioxide, and water vapor. Upstream and downstream NOx sensors provide the Engine Control Module (ECM) with engine-out and tailpipe-out NOx levels.


Check the following items to help determine if the vehicle’s SCR system is operating correctly.


Check for other DTCs

  • Complete repairs as needed for any other DTCs.
  • Clear all DTCs.


Verify DEF (or Reductant) Concentration

  • Using a scan tool, check the reductant concentration in the reductant system data.
  • The reductant concentration temperature reading may be inaccurate if the reductant is frozen or contains ice crystals. If the reductant temperature is below 25 degrees F (–4 degrees C), warm the fluid in the tank (Fig. 9) by parking the truck in a warm environment until the DEF tank temperature is warmer than 25 degrees F (–4 degrees C).
  • If the concentration is not between 28.8% and 36.2%, replace the DEF and continue with the following steps.


Fig. 9


Run the Emission Reduction Fluid Injector Quantity Test

  • If the test does not pass, refer to Emission Reduction Fluid Injector Quantity Test in the appropriate Service Information and then re-run the test.


Perform the Reductant System Malfunction Warning Service Bay Test

  • Warm the vehicle to proper operating temperature; otherwise the Reductant System Malfunction Warning Service Bay Test may time out.
  • If the test passes, return the vehicle to the customer.
  • If the test fails, repeat the Reductant System Malfunction Warning Service Bay Test up to 2 more times. If the test fails after 3 attempts, refer to the DTC P20EE service procedure in the Service Information.


For additional information, refer to #PIP5510B in the Service Information.


– Thanks to John Stempnik


New Global Electronic Parts Catalog Release Delivers Better Results

The latest update to the GM Global Electronic Parts Catalog (EPC) includes several new features that make it easier and more convenient to search for parts and to quickly find the right parts information. GM dealerships can access the EPC through the GM GlobalConnect Parts Workbench.


Search Results in Main Window


One new feature included in the latest release is a single screen in which to search for a part, view an illustration, and add the part to the shopping list — all within the main content area of the EPC. The search results include the same accurate data, but with the results right in the main EPC screen, it’s easy to quickly change vehicles, VINs, or groups without closing the window.


From the search screen, the search can be refined by using the drop-down menu for the make/year/model & Group information. (Fig. 10, A)


A new search using the same VIN can be performed by selecting the Reset button at the top of the screen. (Fig. 10, B) All previously identified parts and the Noun / Part Number, Group and Without search terms are cleared, but the entered VIN is retained. To remove the VIN, select All Makes from the Within drop-down menu, or enter a new VIN.


Fig. 10


Graphic-Driven Navigation


To search using part illustrations, set the Catalog Navigation Style to “Graphical.” (Fig. 11) With the Graphic-Driven Navigation selected, graphical shortcuts can be used when searching to jump right to a particular location. Navigation can be done manually or with a VIN.


Fig. 11


Flashing “I” Note Icon


When viewing an illustration of a part, any important notes will appear with a yellow paper icon above the illustration. Illustration RPO notes are identified with a plain yellow paper icon. If an illustration has a note other than RPO list items, such as user notes or distributor notes, the yellow paper note will appear with flashing “I” on the note icon. (Fig. 12) Select the icon to view the additional information.


Fig. 12


MyPriceLink® Portal


The latest release also includes a new button above the shopping lists that enables all part numbers to be copied, up to 100 part numbers. (Fig. 13) The copied part numbers can be easily entered into the MyPriceLink portal when pricing parts.


Fig. 13


After entering the necessary MyPriceLink information in the Vehicle and Payer section, click the Part Number section and right-click to paste the copied part numbers. Select the Get Price button and follow the normal procedures to continue in the portal.


Launch ACDelco Catalog from Any Screen


The ACDelco catalog also can now be launched directly from any screen in the EPC. Click the ACDelco icon at the top right of the screen to access the catalog. (Fig. 14)


Fig. 14


For assistance or technical support on using any features of the Global Electronic Parts Catalog, send an email to or contact the GM EPC Technical Support help desk at 1-888-994-6372.


– Thanks to Mary Daly

Take the 2017 TechLink Reader Survey

At TechLink, we cover a wide range of GM service topics, from the latest diagnostic and technical repair information to new model features, special tools and more. It’s our mission to provide the latest GM technical news and repair information so that you can quickly and accurately repair the vehicles that come into your service department every day.


Fig. 15


To help us toward that cause, we would like to hear from technicians and other service department professionals in GM dealerships about the topics we cover. What information should we highlight? How much should we cover on different topics? Your input will help in determining the coverage of future editions. So which topics are of interest and value to you?


Click the Survey button or click the Survey link on the right side of the home page to take a short survey about the information you want most in TechLink.



Your input is very important to us. Thanks for taking the time to complete the survey. We’ll share the results soon.


– Thanks to Lisa Scott

Get Real-Time Feedback with the TAC Dealer Case Management System

Did you know the new Dealer Case Management (DCM) system allows U.S. GM dealership service technicians to create, view, and update GM Technical Assistance Center (TAC) cases in real-time? DCM increases the speed and efficiency of case management to help improve communication with technicians, and in turn, enhance the quality and service experience for GM customers.


Using the DCM system, technicians have the ability to quickly communicate back and forth with TAC advisors. (Fig. 1) There is no need to take notes because all communication is documented in the DCM system. A list of case activities at the bottom of the screen show how the case has progressed as well as its current status.


Fig. 1


Currently, users are averaging less than a 15-minute response time for feedback on a case, which means technicians spend less time on the phone and more time addressing customer concerns and building stronger customer relationships.


Dealer Case Management App


To access the DCM, go to the App Center on GlobalConnect. Select Service from the Department drop-down menu and then select Dealer Case Management System & Resources from the list of apps. The DCM launch box will appear. Click the Launch button to open the application. (Fig. 2)


Fig. 2


The system includes case management for the Voice of the Customer (VOC), Customer Assistance Center (CAC), and Technical Assistance Center (TAC). With these systems combined, dealerships can manage all customer issues from one central location.


Training Aids


There are several training aids available for learning about how to use the DCM system. To begin, select the App Resources button that is included in the DCM launch box on GlobalConnect.


From the DCM training main page, select the link to TAC to access specific training materials about using the DCM system for TAC cases. (Fig. 3)


Fig. 3


The training page includes training developed for each specific business unit. It features various types of learning methods based on your preference, including:

  • DCM Reference Guide
  • How-to videos (Fig. 4)
  • Center of Learning Web-based training (four part module)
  • Recorded WebEx sessions
  • Job aids


Fig. 4


Under the Getting Started with TAC tab, technicians can review some of the basics about using the DCM system, such as:

  • How to open a TAC case
  • How to review a TAC case & add attachments
  • How to request to close a TAC case
  • How to search for existing TAC resolutions


TIP: Also check out course VMVDC.M17W2 Dealer Case Management: Technical Assistance Center (TAC) Case Handling on the Center of Learning. It’s a short, interactive course for service technicians.


These DCM TAC FAQs also provide more information. (Fig. 5)


Fig. 5


– Thanks to Elizabeth Hathaway


New GDS2 Core Software Update

A new version (18.1.161) of the GDS2 core software has been released recently. The update includes numerous software bug fixes.


To download the software update, click the GDS 2 icon on the TIS2Web home page. (Fig. 6)


Fig. 6


When updating from one core version of GDS2 to the next, the dealership firewall/antivirus program will recognize it as a new application. You may need to engage your local dealership IT support to ensure GDS2 is entered as an exception in the security programs to allow normal functionality.


Users also need full administrative rights to install the GDS2 core update. If any issues are encountered with GDS2 not functioning properly, right click on the GDS2 icon on the desktop and select “Run as administrator.”


For assistance, contact the Techline Customer Support Center (TCSC) at 1-800-828-6860 (English) or 1-800-503-3222 (French).


– Thanks to Chris Henley

New Universal Refrigerant PAG Oil for R-1234yf A/C Systems

GM has recently released a new refrigerant PAG (Polyalkylene Glycol) oil (Fig. 7) specifically engineered to service GM vehicles built with belt-driven air conditioning (A/C) compressors that use the environmentally-friendly alternative refrigerant R-1234yf.


Fig. 7


Previously, there were multiple PAG oils released to service GM vehicles using R-1234yf (using belt-driven A/C compressors), which required technicians to refer to the Service Information during every A/C service to ensure the correct PAG oil was used.


With the universal PAG oil, the A/C repair process is simplified. Now, there are only two PAG oils needed (for R-1234yf systems and R-134a systems) when servicing GM cars built with belt-driven A/C compressors. (Fig. 8)


Fig. 8


It is acceptable to use any existing inventory of the previously released R-1234yf PAG oils provided that it is the correct oil part number for the specific A/C system. If using a previously released, non-universal oil, always refer to Service Information to ensure the correct refrigerant oil is being used.


Oil Injection Tool


The new universal R-1234yf refrigerant PAG oil comes in the same 8 oz. (240 ml) tubes just as the previous refrigerant PAG oil. These cartridges are designed to be used with oil injection tool GE-45037. (Fig. 9)


Fig. 9


High Voltage Electric A/C Compressors


For high voltage electric A/C compressors (Fig. 10), use only POE (Polyolester) refrigerant oil (GM PN 88862657, U.S., and 88862658, Canada). GM only has one POE oil released for service at this time.


Fig. 10


Current Refrigerant Oils

– Thanks to Chris Semanisin

Left-Hand Thread Cooling System Pressure Test Adapter

The cooling system surge tank for 2017 Silverado and Sierra models equipped with the 6.6L Duramax diesel engine (RPO L5P) features a new design with two tank caps. The fill cap on top of the tank uses a left-hand thread and requires a Cooling System Pressure Test Adapter to pressure test the system.


The tank is placed at a low position in the engine compartment, in relation to the engine, due to space constraints. Based on its location, the tank was designed to have the coolant at the top and the air portion at the bottom of the tank to ensure that the coolant will be at the highest level in the cooling system.


Vented and Non-Vented Tank Caps


The cap located on the lower outboard side of the tank is a standard vented cap with right-hand threads that vents excessive cooling system pressure. (Fig. 11, #2) The cap on the tank top is a non-vented fill cap and has left-hand threads (Fig. 11, #1); this eliminates any attempt at installation of non-vented cap where a vented cap is required. Turn the fill cap clockwise to remove the cap or counter clockwise to install it.


Fig. 11


The top tank cap has two seals (the side surge tank cap also has two seals) to protect from hot fluid exiting through the top portion of the neck itself during hot engine conditions.


Cooling System Leak Testing


The Cooling System Pressure Test Adapter (GE-52098 or GE-52098-A) is a left-hand adapter (Fig. 12) that threads on the tank to allow pressure testing of the cooling system using the previously released Cooling System Pressure Tester (Essential tool J-24460-A, or EN-24460-A).


Fig. 12


The Cooling System Pressure Test Adapter also includes a center core with O-rings that seals off the tank vent port so the test can be run correctly. (Fig. 13) Due to the fill cap being a non-vented cap, an adapter to pressure test the fill cap is not needed.


Fig. 13


TIP: During testing, do not exceed the pressure rating that is printed on the vented cooling system surge tank cap on the lower side of the tank. The cooling system should hold the rated pressure for at least two minutes. Observe the gauge for any pressure loss and inspect the cooling system for any system leaks.


The Cooling System Pressure Test Adapter (GE-52098 or GE-52098-A) is available through


– Thanks to Chuck Berecz and Chris Semanisin


Updated 11/20/17

Common Questions on the New 2018 Terrain

The all-new 2018 GMC Terrain is available with a variety of new features that may be unfamiliar to some customers, who may bring their vehicle into the dealership for service when a system is operating as designed. Be prepared to explain how a particular system operates if your customers ask the following common questions about the new Terrain.


Where can I find more information about all the functions of the new infotainment system?


The next generation of infotainment systems available on the Terrain feature either a 7-inch (178 mm) or 8-inch (203 mm) touchscreen, integrated OnStar features, and personalized, cloud-based user profiles. (Fig. 14) The functionality of the three available systems varies. Apple CarPlay and Android Auto compatibility is standard on all systems. A number of connectivity features are optional, depending on the system.


Fig. 14


Detailed information and videos can be accessed on the GMC owner website at (in Canada, go to Select the 2018 Terrain using the drop-down menus and select Learn About Your Vehicle.


Can the Navigation SD card be used in another vehicle?


The infotainment systems equipped with available navigation (RPO IOU) and standard navigation (RPO IOT) have the map data stored on a SD card. Each Nav SD card is VIN-specific and RPO-specific and cannot be used in another vehicle. If the card is inserted into the SD card slot of another vehicle, the message “SD CARD ERROR” will be displayed on the infotainment screen.


Why does the hands-free power liftgate only work intermittently?


If the power liftgate is equipped with hands-free operation, the liftgate can be opened or closed by using a straight-ahead kicking motion (not a side-to-side sweeping motion) under the rear bumper. The location of the rear bumper sensor is between the left exhaust pipe and the license plate. (Fig. 15) The key fob must be within 3 feet (1 meter) of the liftgate.


Fig. 15


TIP: The liftgate will fully open when the power liftgate control knob is in the MAX position. It also can be programmed to open to a lower height when the control knob is in the 3/4 position.


For additional information about the hands-free liftgate, review Bulletin #17-NA-153.


Why is Lane Keep Assist not functioning?


The customer may be expecting a warning chime when the Lane Keep Assist with Lane Departure Warning system is active. However, there is not a warning chime if the system determines the driver is actively steering.


Lane Keep Assist will provide steering input to gently turn the steering wheel to help center the vehicle in the traffic lane if the vehicle approaches a detected lane marking without using a turn signal in that direction. The Lane Keep Assist icon is green on the instrument cluster if the system is available to assist. The Lane Keep Assist icon will turn amber when the system is providing steering input. As the driver actively steers the vehicle, the steering input and amber indicator may not be noticed.


If the driver does not actively steer the vehicle and crosses the lane marking without using a turn signal in that direction, the Lane Departure Warning will then provide a warning by flashing the amber icon and pulse the Safety Alert Seat or sound a chime/beeps (if selected in the Settings menu).


TIP: The Safety Alert Seat settings can be changed by going to Settings > Vehicle > Collision/Detection Systems > Alert Type on the infotainment system. Audible beeps or seat pulsing alerts may be selected.


The Lane Keep Assist system can be turned on/off using the button on the center console. (Fig. 16)


Fig. 16


For additional information about the Lane Keep Assist system, review #PIT5481B.


Why does the engine turn off at a stop?


The Terrain features Stop/Start technology to help conserve fuel and provide better fuel economy. The system shuts down the engine when the vehicle comes to a complete stop, referred to as an Auto Stop, if operating conditions are met. To indicate an Auto Stop, the tachometer will read AUTO STOP. The audio system, climate controls and other accessories will continue to operate. The engine will restart upon releasing the brake pedal or applying the accelerator pedal. The tachometer will read OFF when the engine is turned off using the ignition pushbutton. (Fig. 17)


Fig. 17


The engine may not turn off at a stop or may restart if any of the following conditions apply:

  • A minimum vehicle speed is not reached.
  • The engine or transmission is not at the required operating temperature.
  • The outside temperature is not in the required operating range.
  • The shift lever is in any gear other than Drive (D).
  • The battery charge is low.
  • The climate control system requires the engine to run based on the climate control or defog setting.
  • The Auto Stop time is greater than two minutes.


Why does the outer window belt molding look out of position?


The outer window belt moldings on some 2018 Terrain models may have poor fit and retention to the doors. (Fig. 18) The original design of the belt moldings did not provide a proper fit to the door surface. If this condition is found, replace the outer window belt moldings with revised moldings that are now available.


For additional information and part numbers, review Bulletin #17-NA-246.


Fig. 18


– Thanks to Kris Villegas

New TAC Action Centers for CT6 Super Cruise and Enclave

The GM Technical Assistance Center, or TAC, (U.S.) has established Action Centers for the 2018 Cadillac CT6 equipped with Super Cruise (RPO UKL) (Fig. 19) and the 2018 Buick Enclave. (Fig. 20)


Fig. 19


TAC Action Centers are designed to gather early feedback and provide support for the introduction of new GM models. Dealership service departments are asked to report all vehicle issues that require immediate attention, not just concerns that require technical assistance. The goal is to develop a quick resolution to any product concerns, such as fit and finish, performance, and operation.


Fig. 20


TAC Action Centers have a direct connection to GM Engineering, Brand Quality and the assembly plant, which offer combined resources to immediately address product concerns seen in the dealership. Each TAC case is sent out to hundreds of people representing engineering, manufacturing, aftersales and other organizations across GM.


If any concerns are encountered with the new CT6 with Super Cruise or Enclave in your dealership, contact the Technical Assistance Center. After entering your dealership’s BAC code, select the prompt for Action Centers.


– Thanks to Steve Jacob

All-New 2018 GMC Terrain Arrives in Style

The all-new 2018 GMC Terrain is sized and designed to meet the needs of the compact SUV customer. It is a five-passenger, four-door, front-wheel-drive (FWD) vehicle, with available all-wheel-drive (AWD).


The new Terrain’s bold exterior highlights GMC’s evolving design. (Fig. 1) Plus, a range of three turbocharged engines, including an all-new 1.6L turbo-diesel engine, provides more choices for Terrain customers.


Fig 1


Turbocharged Engines


The 1.5L Ecotec turbocharged gas engine (RPO LYX) shares architecture with other Ecotec engines, but gets its own unique cam timing (later intake valve closure) and an improved turbocharger to boost performance and economy. It has an aluminum cylinder block and head, which helps reduce the vehicle’s overall mass, and features Central Direct Fuel Injection and Continuously Variable Valve Timing (VVT). It uses ACDelco dexos1 SAE 0W-20 viscosity grade engine oil.


The 2.0L turbocharged gas engine (RPO LTG), which is based on a generation of large displacement four cylinder engines, features a twin-scroll turbocharger that helps optimize usable power from the engine, generating up to 20 pounds (138 kPa) of boost. It uses ACDelco dexos1 SAE 5W-30 viscosity grade engine oil.


The 1.6L turbo-diesel engine (RPO LH7) is efficient, very quiet and offers responsive performance with 240 lb.-ft. of torque. (Fig. 2) Every part on the engine was designed with quiet running operation in mind. Engine noise is barely noticeable for a diesel, even at idle. As a diesel engine, it uses ACDelco dexos2 SAE 5W-30 viscosity grade engine oil.


Fig 2


Diesel emissions are controlled via a Selective Catalytic Reduction (SCR) aftertreatment system that uses urea-based Diesel Exhaust Fluid (DEF), which is housed in a 4.9-gallon (18.5 L) tank. It needs to be replenished about every 7,500 miles (12,070 km), the same as the vehicle’s recommended oil change interval during typical operation. A graphic on the Driver Information Center displays OK until the DEF reaches a predetermined amount of remaining life expectancy, at which point the remaining DEF life is displayed in percentages. The DEF fill point is located in the fuel-filler door.


Fuel-saving stop/start technology is standard on all three engines. The stop/start system includes:

  • A tandem-solenoid starter that enables the engine to restart quickly and smoothly.
  • A unique DC-DC module that maintains voltage during a stop/start event to avoid lighting fluctuations and potential resets/noise in the audio/infotainment system.
  • An electronically-controlled accumulator that retains the transmission fluid pressure to keep the clutches engaged for immediate takeoff when the brake pedal is released.
  • Torque-reaction engine mounts that dampen vibrations associated with an engine restart.


The 1.5L and 2.0L turbocharged gas engines are matched with two unique 9-speed automatic transmissions. The HydraMatic 9T45 9-speed transmission (RPO M3U) is used with the 1.5L gas engine and the HydraMatic 9T50 9-speed transmission (RPO M3H) is used with the 2.0L gas engine.


The HydraMatic 6T45 6-speed automatic transmission (RPO MHG) is used with the 1.6L diesel engine.


Electronic Precision Shift


GMC’s new Electronic Precision Shift replaces the conventional transmission shifter with an electronically-controlled gear selection that consists of intuitive push buttons and pull triggers, which enables more storage room in the center console. (Fig. 3)


Fig 3


Located at the bottom of the center stack, the system features a row of buttons and switches. Park (P), Neutral (N), and Low (L) are selected by pushing the appropriate button, while Reverse (R) and Drive (D) are engaged by pulling on the R and D switches. The Low range — or selecting among the nine gear ratios — is engaged by pressing the plus (+) or minus () button.


In addition, the Terrain comes standard the driver-controllable Traction Select system, which offers choices for different driving conditions, and changes the throttle response and other calibrations for the selected driving mode.


AWD Terrain models also include a FWD mode, with a switchable On-Off feature (Fig. 4), that mechanically disconnects the AWD system to minimize drag and optimize fuel economy in normal, everyday driving conditions.


Fig 4


Chassis Features


The Terrain has a MacPherson strut front suspension with side-loaded modules, specifically tuned coil springs and a direct-acting stabilizer bar, along with a four-link independent rear suspension. (Fig. 5) 17, 18 or 19-inch aluminum wheels are available, depending on the model.


Fig 5


The dual rack and pinion Electric Power Steering (EPS) system incorporates Lead-Pull Compensation, which automatically adjusts the steering angle to account for factors like crowned roads or high crosswinds, which can typically cause the driver to turn the steering wheel slightly to maintain a straight path. Sensors detect the steering correction and adjust the torque applied to the steering system to relieve the effort on the driver, helping to maintain straight driving with less input.


The four-wheel disc brakes feature low-drag calipers. In a conventional disc brake system, there is always slight contact between brake pads and the rotor, even when the brakes are released, which creates rotational resistance (or brake drag) on the rotor that negatively affects fuel economy and can cause uneven rotor wear and vibrations when braking. The low-drag calipers incorporate specially designed components to ensure that the pad-to-rotor gap is precisely maintained and that reduced slide forces are kept throughout the life of the vehicle, contributing to improved fuel economy.


Infotainment System


A significantly enhanced infotainment system (Fig. 6), making its GMC debut on Terrain, comes standard with a 7-inch (178 mm) diagonal color touchscreen or an available 8-inch (203 mm) diagonal color touchscreen. The versatile system has three versions, all of which have Apple CarPlay™ and Android Auto™ compatibility.


Fig 6



  • 7-inch color touchscreen
  • Cloud services and Shop not included



  • 8-inch color touchscreen
  • 90 days of Cloud services
  • In-vehicle apps via Shop



  • 8-inch color touchscreen
  • 3 years of Cloud services
  • In-vehicle apps via Shop
  • Standard Navigation


Safety Features


An expanded range of radar- and camera-based active safety technologies are available on the 2018 Terrain, all designed to enhance driver awareness and help make it easier to park and maneuver in low-speed situations.


Some of the available safety features include:

  • Safety Alert Seat
  • Surround Vision camera system
  • Forward Collision Alert (Fig. 7) with Following Distance Indicator
  • Low-Speed Forward Automatic Braking
  • Lane Keep Assist with Lane Departure Warning
  • Lane Change Alert with Side Blind Zone Alert
  • Rear Cross Traffic Alert
  • Rear Parking Assist
  • IntelliBeam high-beam headlamp control


Fig 7


Special Tools


The following special service tools have been released for the 2018 Terrain:

For additional information on the new 2018 Terrain, refer to Bulletin #17-NA-254.


– Thanks to Sherman Dixon and Kris Villegas


Questions to Ask for Bluetooth Concerns

What’s one of the first things drivers do after entering their vehicle? If you said use their mobile phone, you’re correct. A recent study shows that the average driver spends 3.5 minutes on the phone per one hour trip. This makes understanding how their phone connects to the vehicle’s Bluetooth system and its operation critical to customer satisfaction.


Helpful customer information about the operation of the Bluetooth system and related systems in GM vehicles can be found at the online Owner Center for Chevrolet, Buick, GMC or Cadillac models. The websites provide a variety of information related to vehicle technology and connectivity. Also refer to the vehicle’s Owner’s Manual for more information.


If a customer has a concern about using the Bluetooth components, it’s important to explain that the functionality of Bluetooth can vary with each component, software level and service provider. Because of these variables, it’s critical to gather as many details as possible before diagnosing a Bluetooth condition.


If a customer has concerns with a specific Bluetooth device, it will be more helpful to leave the device with the vehicle so that the system can be properly diagnosed.


TIP: If a paired device or infotainment module has recently received an update, the device will need to be deleted from the vehicle list and the vehicle will need to be deleted from the device and a fresh pair performed. (Fig. 8)


Fig 8

Before contacting the GM Technical Assistance Center, answers to the following questions should be gathered.


Customer Questions


  • What is the customer concern?
  • When does the customer concern occur?
  • When did the concern start to occur?
  • Is the concern intermittent or does it happen regularly?
  • Can the customer demonstrate the concern?
  • Where is the exact location of the device when this concern occurs (In a purse on passenger seat, etc.)?
  • What brand and model of device is being used?
  • Which service provider does the customer’s device use? What software version is installed on the device?
  • According to the online Owner Center, (U.S.) or (Canada), should the device be compatible with the vehicle and should the desired feature be supported for the customer’s vehicle and device?


Technician Questions


  • Does the same concern occur in this vehicle when using a known-good device?
  • Does the same concern occur when using the customer’s device in a known-good vehicle?
  • Have any Service Information documents, PIs, and/or Bulletins been performed.
  • Are any aftermarket accessories used in the vehicle?
  • Are any DTCs set in any control modules?
  • What diagnosis has been performed so far?
  • Have any parts been replaced?
  • Is the vehicle equipped with Generation 8 or 9 of the VCIM/OnStar Module? If so, is the vehicle equipped with RPO UPF (OnStar Bluetooth)? How many devices are connected to the vehicle (a maximum of 5 devices are allowed — document them)?
  • What is the RPO of the radio and which software version is installed?


– Thanks to Jamie Parkhurst


  • [+]2017
  • [+]2016
  • [+]2015
  • [+]2014