Archive for November 2014

Vehicle Health Management Service Monitors Potential Performance Conditions, Notifies Owners

The new Vehicle Health Management (VHM) service available to owners of a 2015 Equinox or Terrain equipped with the 3.6L V6 engine (RPO LFX) monitors the engine cranking and fuel delivery systems for various performance issues. If an issue is identified, the VHM service sends a message via OnStar® to the Customer Assistance Center (Customer Care Centre in Canada) to contact the owner and help schedule a service appointment. (Fig. 1)


The VHM service is designed as a preventative measure to help owners avoid potential vehicle performance conditions. Owners must enroll in OnStar Vehicle Diagnostics and the VHM service.



Fig 1


The VHM service monitors the engine cranking system — battery and starter performance — and the fuel delivery system — fuel tank fuel pump module and fuel pressure sensor performance — to identify and help prevent various conditions. The VHM service communicates with OnStar only once per ignition cycle.


TIP: Since the VHM service is monitoring the systems for potential conditions, some service messages may be generated without any apparent symptoms being noticed by the driver.


Communicating with Owners


When a VHM service message is triggered, a message is sent via OnStar to the Customer Assistance Center (or Customer Care Centre) to contact the owner and set up a service appointment with the owner’s preferred dealership. The Customer Assistance Center (or Customer Care Centre) also will contact the dealership to assist with the appointment and communication of the VHM service message. The owner and dealership also will receive the service message information by email.


Dealership personnel with any questions about a particular VHM service message received at the dealership should contact the Dealer Business Center (U.S.) or Customer Care Centre (Canada).


Service Message Identifiers


To classify potential issues identified by the VHM service, nine different Service Message Identifiers are used. These are not Diagnostic Trouble Codes (DTC). The identifiers, which combine the related Service Information section with a number, can be used in a Service Information key word search. For example, 12 volt battery is covered under the Starting and Charging section, so the first battery Service Message Identifier is SAC001.


VHM Service Message Identifiers are not stored in the vehicle and cannot be retrieved using a scan tool as would a DTC. Currently, the Service Message Identifiers are only included in the customer communications. Related on-board DTCs may or may not be set.


To begin vehicle diagnosis and repairs, review the Service Message Identifier in the message provided by the owner or the Customer Assistance Center (or Customer Care Centre).


TIP: Due to the unique nature of the VHM service, special Bulletin Only Labor Operations have been set up for repairs of identified service messages. These Bulletin Only Labor Operations must be used for any repairs related to a service message.


Diagnostic Procedures


Following are the Service Message Identifiers for the VHM service. Refer to #PI1250 for complete diagnostic procedures for each identifier.


Screen Shot 2014-11-19 at 3.09.15 PM


TIP: Parts replaced during repairs of identified VHM service messages may be requested to be returned to the Warranty Parts Center.


Once the proper repairs have been made, the VHM service will clear the service message after the vehicle is operated over a number of ignition cycles. If other on-board DTCs have set, clear them prior to releasing the vehicle to the owner.


For additional information about the VHM service, including Labor Operations, refer to #PI1250.


– Thanks to Ray Romeo and Len Tillard

1.2L Engine Piston Installation Tool

When installing the pistons on the 1.2L 4-cylinder engine (RPO LL0) in 2013-2015 Sparks, all piston rings, including the oil expander ring, must be properly positioned prior to clocking or piston, piston ring or cylinder wall damage may result. (Fig. 2)


F02 3999419

Fig 2


Validating the proper ring positioning can be difficult due to the small size. The WISECO RCS07061 ring compressor sleeve (Fig. 3), a commercially available tool for piston installation in this engine, is now available to validate proper piston ring positioning prior to installation, reducing the possibility of damage.


F03 3999432

Fig 3


The WISECO RCS07061 ring compressor sleeve is a cone-style piston installer that will not allow the piston/ring assembly to pass if the piston rings are not properly positioned. The photos show the proper positioning of the oil control expander ring (Fig.4) and an overlapped, improperly positioned oil control expander ring. (Fig. 5)


Once proper ring positioning is established, the piston will install in the cylinder bore with very little effort.


F04 3999428

Fig 4


F05 3999423

Fig 5


– Thanks to Raymond Haglund

Air Cleaner Housing Hydro Carbon Absorber

Some 2013-2015 Encore, Trax (Canada) and 2015 Trax (U.S.) models equipped with the 1.4L 4-cylinder engine (RPO LUV) may have DTCs P0171 (Fuel Trim System Lean) and/or P1101 (Intake Air Flow System Performance) set as current or history DTCs.


If the appropriate Service information diagnostics do not isolate the cause of the condition, inspect the ID code on the air cleaner housing. (Fig. 6)


F06 4006583

Fig 6


The correct application for the 2013-2015 Encore and Trax will have an ID code of ACD and will be fitted with a hydro carbon absorber. (Fig. 7)


F07 4006213

Fig 7


If the hydro carbon absorber is missing, or the ID code is other than ACD, replace the air cleaner housing with the latest listing in the electronic parts catalog.


– Thanks to Raymond Haglund

Engine Block Deck Surface Appearance

During engine block service on some 2011-2015 Cruze, Volt; 2014 ELR; 2013-2015 Encore; 2013-2015 Trax (Canada); 2015 Trax (U.S.); 2012-2015 Sonic; 2004-2012 Aveo; 2005-2009 Wave (Canada); and 2009-2010 G3 models equipped with the 1.4L engine (RPOs LUU, LUJ, LUV), 1.6L engine (RPOs L91, LXV) or 1.8L engine (RPOs LUW, LWE), improper block deck cleaning methods may result in lines in the block deck surface. (Fig. 8) These lines may be mistaken for cracks. (Fig. 9)


F08 4006571

Fig 8


F09 4006573

Fig 9


These lines are the result of using abrasive pad/bristle devices to clean the gasket surface of the engine components. It only takes about 15 seconds to remove 0.203 mm (0.008 in) of metal with an abrasive pad.


TIP: See the latest version of Bulletin #00-06-01-012 for complete details on the use of abrasive devices.


If improper cleaning methods are used, it cannot be determined if the integrity of the sealing surface has been compromised.


The block deck surface lines are not a warrantable condition and should not be claimed as a warranty repair.


Slight traces of these lines seen after using the proper gasket surface cleaning methods will not affect cylinder head gasket sealing.


– Thanks to Raymond Haglund

A/C System Information Needed When Calling TAC

When technical assistance is requested for poor A/C performance conditions on 2015 and prior GM passenger cars and trucks, certain information is helpful for the GM Technical Assistance Center (TAC) in assisting with diagnosing the vehicle.


Before calling the TAC, the following information should be available:

• A/C High and Low pressures

• Outside temperature

• Humidity

• Vent temperature


If the unit is equipped with an Automatic HVAC system, retrieve the following HVAC data with a scan tool:

• Inside temperature sensor reading

• Outside temperature sensor reading

• Duct temperature sensor readings

• Evaporator temperature sensor reading (if equipped)


In addition, callers should always be prepared to provide SI Doc ID(s) or Bulletin/PI numbers when calling the TAC.


– Thanks to Jim Miller



Sunroof Reverses when Closing at Highway Speeds

When closing the sunroof (RPO CF5) while driving some 2015 Escalade models, Silverado, Suburban, Tahoe, Sierra, Yukon models; and 2014 Silverado 1500 and Sierra 1500 models at highway speeds, the sunroof (Fig. 10) may reverse when it reaches the air deflector.


2015 Cadillac Escalade

Fig 10


As the sunroof is closing it must push the air deflector down before closing completely. At highway speeds, the wind resistance against the air deflector may make it hard to push down. The additional effort needed to push down the air deflector may be detected by the sunroof as an object, which may cause the sunroof to reverse operation.

F11 sunroof motor

Fig 11


To correct this condition, replace the sunroof actuator motor (Fig. 11), which has updated software. It will be necessary to relearn the motor. Refer to the Sunroof Motor/Actuator Initialization/Teach Process in the appropriate Service Information.


– Thanks to Jim Will

Fuel Injector and Oil Ring Seal Replacement

If Service Information diagnostics indicates a fuel injector (Fig. 12) may need to be removed for a repair or replaced, such as for a fuel odor or extended cranking condition, on a 2014-2015 Corvette, Silverado, Suburban, Tahoe, Sierra, Yukon, or Yukon XL equipped with the 4.3L engine (RPO LV3), 5.3L engine (RPO L83) or 6.2 engine (RPOs L86, LT1, LT4), be sure a new O-ring seal is installed.


TIP: If an injector is being replaced, all the injectors should be installed with new seals.


2014 "LT-1" 6.2L V-8 VVT DI  Direct Injection Fuel System

Fig 12


The following fuel injector part numbers require a new O ring before installation. Use the O-ring seal listed below.


RPOs LV1-LV3-L83-L86-LT1 Seal Kit (PN 12668553) should be used for the following injector kits:


LV1-LV3-L83 Service Injector:

• 12656932 (Nominal Flow)


LT1/L86 Service Injectors:

• 12656931 – Nominal Flow

• 12660002 – Low Flow

• 12660003 – High Flow


RPO LT4 Seal Kit (PN 12668554) should be used for the following injector kits:


LT4 Service Injectors:

• 12661029 – Nominal Flow

• 12661030 – Low Flow

• 12661031 – High Flow


– Thanks to Richard Renshaw


Rough Idle Condition

A rough idle or idle shake condition may be present on some 2013-2015 ATS sedans and 2015 ATS coupes equipped with the 3.6L HFV6 engine (RPO LFX).


Confirm that the engine does not have any DTCs set and is not exhibiting any misfires or other drivability concerns. If there are no drivability concerns, a new engine mount has been developed to address the rough idle condition.


Replace both left and right engine mounts following the appropriate Service Information procedures. The engine mounts are to be replaced in pairs.


TIP: When installing an engine mount (Fig. 13, A), ensure the phenolic spacer (Fig. 13, B) is in place and not damaged. The phenolic spacer must be present to prevent galvanic/corrosive reaction and/or excessive temperature conduction between the engine mount bracket and the engine mount. Failure to ensure the phenolic spacer is intact and not damaged can lead to premature failure of the engine mount and/or engine mount bracket.

F13 engine mount

Fig 13


– Thanks to Aron Wilson


AFIT Update for the 2.5L 4-Cylinder Engine

The 2.5L 4-cylinder engine (RPO LCV) available in the 2013-2015 ATS and 2015 Colorado and Canyon uses two different ECMs. The E39A ECM is used in the ATS and the E80 ECM is used in the 2015 Colorado and Canyon. The controller connectors are the same but the controller internal circuits and the pinouts are different.


The Active Fuel Injector Tester (AFIT) Spark Ignited Direct Injection (SIDI) Diagnostic Kit, essential special tool CH-47976-500A, includes cable CH-47976-502A that will plug into both controllers. However, the AFIT will not function correctly with the 2.5L engine in the Colorado and Canyon at this time. The AFIT will display an error code and the fuel tank pressure sensor may be damaged and require replacement. The AFIT functions correctly with the 2.5L engine in the ATS.


Currently, the AFIT should not be used with the 2.5L engine in the 2015 Colorado and Canyon. The 2015 AFIT software update that was posted to the GM Dealer Equipment website on September 10, 2014 incorrectly listed the 2.5L 2015 Colorado/Canyon as a selection in the database.


New software has been posted on the GM Dealer Equipment website that has the 2015 2.5L Colorado/Canyon application removed from the database so it cannot be selected in the AFIT menu. Download this software through the Service Workbench selection of “Essential Tools – Software Updates” in GM GlobalConnect (U.S. only).


If you are experiencing difficulty or haven’t registered with GM Dealer Equipment, go directly to for software updates and additional information. (Fig. 1)


In Canada, the software is available through the Dealer Equipment Services (DES) Canada website. A link to this site is in the GlobalConnect library under Service/Tools and Processes and Equipment/Essential Tools – Software Updates.


F01 gmde afit

Fig 1


Until further notice, when servicing the 2.5L engine in the 2015 Colorado and Canyon, technicians are to temporarily use the on-board injector balance test procedure in the appropriate Service Information with the GDS 2 scan tool. An update is being developed that will allow AFIT compatibility with the 2.5L engine in the 2015 Colorado and Canyon. The update will consist of a new software download from the GM Dealer Equipment website and a new adapter cable that plugs into the AFIT Drive & Measurement Unit (DMU) and the 2.5L engine in the Colorado and Canyon engine harness. The cable will ship to USA tier 1-4 dealerships and all Canadian dealerships.


The coding in the software update provides a warning if the 2.5L ATS cable is connected to the 2.5L engine in the Colorado and Canyon and power outputs from the AFIT to the vehicle will be cut until the software senses the new 2.5L Colorado/Canyon adapter cable has been connected.


– Thanks to Charles Berecz

USB Drives for SPS Programming

The Techline Customer Support Center has received inquiries regarding programming concerns with certain brands of USB drives.


Depending on their configuration, some USB drives may be recognized as a hard drive instead of a removable drive, which introduces several issues for a great deal of applications, USB utilities, etc.


When using a USB drive (Fig. 2) for SPS programming, it’s critical that the USB drive meet the necessary specifications. Prior to purchasing a USB drive for use in the service department, review the Dealership PC and Infrastructure Guidelines.


F02 1510

Fig 2


The guidelines are updated a minimum of twice a year. Go to to review the guidelines, including specifications outlining “what is” versus “what is not” supported for Techline applications. In Canada, the IT guidelines are located in the Service Library under Tools, Processes and Equipment on GlobalConnect.


The following requirements pertain to USB drives:

• For Service Programming (SPS) purposes, a dealership may be asked to purchase a USB drive to perform programming on a Radio/Navigation or Instrument Panel Cluster (IPC) system.

• The specification to be used when purchasing a USB drive is a USB 2.0 compliant flash drive no less than 4 GB and no greater than 16GB (formatted FAT32)


TIP: To ensure proper vehicle selection when reprogramming a radio using SPS, it is recommended to use the vehicle VIN within SPS. This way the system selects the correct vehicle information, including all applicable option codes, and loads the correct software for that particular vehicle.


If you have questions regarding USB drives, contact the Techline Customer Support Center (TCSC) at 1-800-828-6860 (English) or 1-800-503-322 (French).


– Thanks to Chris Henley


Water in Driver’s Foot Well

Water may be noticed in the driver-side foot well inboard area on some 2014 Equinox and Terrain models built between March 17, 2014 and May 15, 2014. This condition may be noticed mostly in high humidity climates with the air conditioning system running at higher blower speeds or when turning the vehicle around sharp corners.


The water leak may be due to a void/hole in the lower HVAC case near the heater and air conditioning evaporator and blower module drain. (Fig. 3)


F03 HVAC case

Fig 3


If a void/hole is found in the lower HVAC case, near the accelerator pedal, use approximately 50 mm (2 inches) of 3M Ribbon Sealer or equivalent to fill the cavity. (Fig. 4) Prepare the cavity by sanding with 80-100 grit sandpaper and clean it with an alcohol prep wipe. Allow it to dry before applying the sealer.



Fig 4


When inserting the sealer, fold it in half and apply light pressure until the cavity is filled. (Fig. 5)



Fig 5


TIP: Do not use a silicone or epoxy sealer, which could enter the drain tube (Fig. 6) and cause a blockage.



Fig 6


Verify the sealer is properly in place by running the blower motor at the high setting with the recirculation mode off. No air pressure should be felt over the repaired area.


This repair will save time compared to replacing the lower HVAC case. Refer to #PI1327 for more details and parts information.


– Thanks to Doug Daugherty


6.2L Engine Bell Housing Rattle

A rattle noise at the engine bell housing may be heard on some 2014-2015 Corvettes built with the 6.2L engine (RPO LT1) and an automatic transmission.


Follow the appropriate Service Information diagnostic procedures to determine if the rattle noise is coming from the Driveline Support Assembly (DSA) or the transmission flex plate. If the rattle is coming from the flex plate, it will only be heard at idle from the front of the vehicle while in Park.


If it’s determined that the rattle noise is coming from the flex plate (Fig. 7), raise the vehicle on a hoist and pull the front bell access cover. The noise will be coming from the hole.


F07 flex plate

Fig 7


TIP: Check that the pinch clamp bolt is tight before replacing the front flex plate. The loose bolt condition results in the same noise. This is an easy check before starting a major service procedure.


Do not reinstall the old flex plate even if it looks OK as the cause of the rattle may not be visible.


Unlike the flex plate rattle, a DSA rattle noise typically occurs at or just off idle and will be louder when observed via the rear bell housing access plug. (Fig. 8)


F08 access plug copy

Fig 8


When performing repairs for a flex plate rattle or DSA rattle, refer to the latest information in the Service Information:

• #13-04-17-001 – Driveline Support (Torque Tube) / Propeller Shaft Input to Front Hub Bearing Alignment

• Document ID 3973764 – Driveline Support Assembly Replacement (with Automatic Transmission)


– Thanks to Tracy Lucas

History DTCs Stored in the T6 Power Inverter Module

On some 2011-2015 Volt and 2014 ELR models, DTC P0335 (Crankshaft Position Sensor Circuit) and/or P0336 (Crankshaft Position Sensor Performance) may be stored in history in the T6 Power Inverter Module (Hybrid Powertrain Control Module, or HPCM).


If DTCs P0335 and/or P0336 are stored in history, check that ground locations G106 (engine block) (Fig. 9, A) and G113 (drive unit case) (Fig. 9, B) are clean and tight. On rare occasions, the bolt hole for G113 may not be drilled to the proper depth, which will cause the ground bolt to bottom out in the hole and result in low clamp load on the ground eyelet.


F09 G113

Fig 9


If the ground bolt is tight, but the G113 eyelet is still loose, remove the ground bolt and source a shorter bolt of the correct thread. Install the shorter bolt to the proper torque and retest for any concerns.


If both grounds are clean and tight, with sufficient clamp load on the ground eyelets, attempt to reproduce the DTCs. If the DTCs do not reset, clear the DTCs and do not attempt any repairs at this time.


If the vehicle is a 2014 model, update the T6 Power Inverter Module (HPCM) with the current software in TIS2Web.


If either the DTC P0335 or P0336 is stored in the ECM as well as the HPCM or are current DTCs, follow the diagnostics in the appropriate Service Information.


– Thanks to Raymond Haglund

Engine Pop/Knock at Idle

An engine pop/knock noise at idle may be noticed on some 2012-2014 Captiva Sport models equipped with the 2.4L engine (RPO LEA). The noise usually diminishes as the engine RPM increases. Misfires on some cylinders also may be observed.


If the engine pop/knock noise is present, remove the accessory drive belt to verify that the noise is not accessory drive belt related.


Next, check G109 for sufficient clamp load. (Fig. 10) It should not be possible to twist the cable/wire and make the ground rings move. Also remove the G109 ground ring terminals and inspect for a sticky substance covering the ground rings. Clean this or any other substance off the ground rings and reinstall. This may correct the condition.


F10 G109

Fig 10


When the popping/knocking noise is occurring, check if the timing is being retarded and if there is any knock sensor activity. Disconnect the knock sensor to see if the noise changes. If the timing retards and the noise changes with the knock sensor disconnected, reconnect the knock sensor and disconnect the MAP sensor to see if the knocking noise is affected.


If the noise is not affected by the disconnected MAP sensor, remove both camshaft actuators and inspect the camshaft dowel pin for damage. If damage is found, replace the actuator and camshaft


If there is no problem found with the camshaft dowl pin, remove the piston/rod assemblies and check for excessive clearance in the piston pin bushing. Replace the bushing if necessary.


– Thanks to David Rutkowski

Whistle Noise from the Instrument Panel

On some 2015 Colorado and Canyon models, a whistle noise may be heard coming from the instrument panel when the HVAC system is being used. The sound may be present when driving or when the vehicle is parked.


The whistle noise may be caused by poor installation or fit of the cabin air filter cover. Check if the noise is coming from around the cabin air filter cover by removing the glove box door (refer to the Instrument Panel Compartment Door Replacement procedure in the Service Information) and then setting the HVAC blower at a Low or Medium fan speed.


If the noise is heard coming from around the cover, verify that the cover is properly installed. It may be necessary to remove the door and reinstall it. Make sure the two snaps on the end of the cover are fully engaged and that the “tongue & groove” interface around the perimeter of the door to the module is fully engaged. (Fig. 11)


F11 4006279

Fig 11


– Thanks to Kenneth Cole

Automatic Door Locks

Some owners of 2015 Escalade models, Silverado, Suburban, Tahoe, Sierra, Yukon models; and 2014 Silverado 1500 and Sierra 1500 may request to have the automatic (auto) door lock feature disabled and/or they state they cannot find an auto door lock off selection in the Vehicle settings in the personalization menus. The auto door lock feature has been standard since the 2005 model year and all Body Control Modules (BCM) are programmed from the factory to lock all doors either when the transmission is shifted into gear or with vehicle speed.


There is not a selection in the Vehicle settings and no BCM calibrations have been released to disable the auto door locking feature.


TIP: These models have a unique double pull inside door handle that will unlock and open the door. (Fig. 12) The first pull of the inside door handle will unlock the door and the second pull will open the door.


F12 door handle

Fig 12


– Thanks to Jim Will

Service Know-How

10214.11D – Emerging Issues

November 13, 2014


To view Emerging Issues seminars:

• Log in to

–   Select Resources > Service Know-How/TECHAssist > Emerging Issues > Searchable Streaming Video; or

–   Select Catalog to search for the course number, and then select View > Take or Continue Course


Car Issues – Fix It Right the First Time

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Truck Issues – Fix It Right the First Time

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