Archive for January 2016

The New 2016 Chevrolet Volt Takes Charge

The 2016 Chevrolet Volt is a 4-door, 5-passenger hatchback (Fig. 1), offered in LT and Premier models, with an electric range that has increased to 53 miles — a nearly 40 percent increase over the first-generation model. A 1.5L range-extending engine using regular unleaded fuel allows for further travel.


F01 2016-Chevrolet-Volt

Fig. 1


Highlights for the 2016 model include:

  • The Regen-on-Demand™ feature the driver can use to control the vehicle’s energy regeneration with a paddle on the back of the steering wheel.
  • Stronger body structure with more high-strength steel and a quieter ride.
  • New braking system with improved capability.
  • 120 V portable charging cord set boasting a simpler, compact design and more convenient storage location.
  • Active grille shutters help balance design with efficiency.
  • Available illuminated charge port.


The Volt also features 10 air bags, a rear vision camera, and crash-avoidance items such as Lane Change Alert, Rear Cross Traffic Alert, Forward Collision Alert and Front Automatic Braking.


Driving Modes


Four driving modes are available on the 2016 Volt, which you access by pressing the MODE button on the center console. Scroll through a menu on the instrument cluster to select the preferred mode, which will become active three seconds after it is selected. (Fig. 2)


F02 drive modes

Fig. 2


The four driving modes are:


• Normal (Default) – Activates when the vehicle is started, and is used normal driving conditions for efficient operation.

• Sport – Increases throttle response and power delivery characteristics for a sportier driving experience.

• Mountain – Best deployed when in mountainous terrain (long grades of 5% or steeper); helps to preserve battery power and will also work to maintain higher speeds.

• Hold – Forces the Volt into extended range operation to maintain battery charge.


TIP: The Volt shouldn’t be kept out in extreme weather conditions for long periods without being driven or plugged in.


Pushbutton Start


The Volt features an electronic pushbutton start. Press the Power button once to put the vehicle in on/run position; when the Ready light appears in the instrument cluster, the vehicle can be driven. This process can take up to 15 seconds in extreme cold.


If the Power button is pressed while the vehicle is moving, a message in the Driver Information Center will prompt the driver to turn off the Volt by pressing the Power button again.


Climate Control Systems


There are three settings — Fan Only, Eco and Max — that have a direct effect on the Volt’s electric range and fuel economy.


In the eco mode, air conditioning and heat is controlled to maintain fuel economy while still providing some comfort. MAX mode delivers the best comfort level based on the temperature setting chosen. Electric range and fuel economy will decrease in relation to the energy required to meet this level.


In both modes, you can have the air conditioning and heat on at the same time, or have the A/C run with the Defrost/Defog.


Heated Seats


The Volt features optional heated front and rear seats. There is an automatic heated seats feature for the front seats that can be programmed to be activated when the vehicle is on. If the front passenger seat is not occupied, the feature will not heat that seat. With the auto feature, the seat heating level will change to what is required by the vehicle’s interior temperature.


During a remote vehicle start, the heated seats will turn on automatically in cold weather. The feature must first be enabled in the Vehicle Personalization menu.


Battery Charging


A new feature for charging the Volt is programmable charging using GPS, which enables owners to be able to set their charging preferences exclusively for their “home” charging location. The vehicle will automatically adjust to that setting when it’s at that location. Owners will only have to program the system once and the Volt will return to those settings every time it’s at the home location.


Owners can pre-set their battery charging level at 240 V or 120 V, which can be set on either 8 A or 12 A and whether they wish to charge immediately, set a departure time for each day of the week, or set a departure time and a utility rate schedule to charge only at off-peak rates.


Charging Times


• Charge Station: 240 V, 16 A: Approx. 4.5 hours.

• Portable Cord set: 120 V, 8 A: Approx. 19 hours. (Default setting)

• Portable Cord set: 120 V, 12 A: Approx. 12.5 hours.



Charging Status


A new charging status feature includes a specially designed tone that indicates when charging has begun, with additional tones sounding for delayed charging. A charging status indicator light (on the top of the instrument panel) shows the approximate charge level through a series of flashes. (Fig. 3)


F03 charging status

Fig. 3


When the vehicle is plugged in and the battery is charging, the number of flashes indicates the percentage of battery charge. For example, one flash = 0–25% charged, two flashes = 25–50% charged, three flashes = 50–75%, etc. A solid light means the battery is fully charged. In addition, solid or flashing green or yellow indicator lights (with tones) can communicate certain charging information as well.


TIP: Advise customers that when charging, the system may run fans and pumps that may produce sounds even when the vehicle is turned off. Additional unexpected clicking sounds may be caused by the electrical devices used while charging. This is normal.


120 V Portable Charging Cord Set


A new 120 V portable cord set includes a cord that is now nearly 25-feet long and can be locked using a small padlock to deter unauthorized removal during charging. Plus, for improved accessibility, a new storage bin for the cord is located on the left side of the rear cargo area above the load floor. (Fig. 4)


F04 Charge cord stored

Fig. 4

The 120 V Gen 1 portable charge cord will work on the new Volt. However, it is not recommended since the Gen 2 cord has an internal resistor that can detect increasing temperatures caused by a faulty or loose wall plug.


The drive motor battery charger cable has two indicators — the AC Present Indicator and the Fault Indicator — which display its status.

• A solid green AC Present Indicator means AC voltage is present at the wall plug and there are no faults.

• A flashing green AC Present Indicator and solid red Fault Indicator indicates the electrical outlet or plug is faulty or overheated.

• A solid red Fault Indicator shows that the AC outlet does not have a proper ground and charging is not permitted for safety reasons.

• A flashing red Fault Indicator means a vehicle fault has occurred and the charger cable ground-fault circuit interrupter (GFCI) has tripped.

• A solid green AC Present Indicator and flashing red Fault Indicator occurs when the charger cable has failed the self-check.


– Thanks to Sherman Dixon, Keith Newbury, Steve Falko and Chuck Wieseckel


New Volt Propulsion System

The all-new Voltec extended-range electric vehicle (EREV) propulsion system in the new Volt is even more efficient for 2016, providing greater EV range (up to 53 miles on electricity), improved fuel economy and stronger acceleration than the previous generation.


System components (Fig. 5) include:

1. Drive Motor Battery Charger

2. Accessory DC Power Control Module

3. Rechargeable Energy Storage System (RESS)

4. Charge Port Receptacle

5. 5ET50 Electrified Transaxle

6. 1.5L Range Extender Gasoline Engine

7. Power Inverter Module.


F05 propulsion

Fig. 5


High-Voltage Battery System


GM’s industry-leading battery technology is improved for 2016 and includes revised cell chemistry that increases energy storage capacity by 20 percent on a volume basis versus the original cell. The cells are also positioned lower for an improved (lower) center of gravity and the overall mass of the pack has decreased by almost 20 pounds (9 kg). (Fig. 6)


F06 battery pack

Fig. 6


High-voltage battery system features include:

• Battery Type: Rechargeable energy storage system comprising multiple-linked modules

• Mass: 403 lbs. (183 kg)

• Chemistry: Lithium-ion

• Thermal system: Liquid active thermal control

• Cells: 192 Lithium-ion

• Cell Groups: 96

• Energy: 18.4 kWh, of which approximately 14.2 kWh are usable in order to extend the life of the battery.


Enhanced Twin-Motor Drive Unit — Power Inverter Module  


The Volt’s new drive unit was engineered with a focus on increased efficiency, performance, improved packaging and reduced noise and vibration. The enhanced twin-motor drive unit operates approximately 5 to 12 percent more efficiently and boosts torque while weighing 100 pounds (45 kg) less than the previous unit. (Fig. 7)


F07 drive unit

Fig. 7


The Power Inverter Module manages power flow between the battery and the electric drive motors and is built directly into the drive unit to reduce mass, size and build complexity while further improving efficiency. The module receives and monitors driver commands and other sensor inputs and uses this information to vary the torque and speed of each electric motor-generator (Motor A and Motor B) and to command the engine controller and engine operation.


The Power Inverter Module — Motor A and B — high-voltage connections (Fig. 8) include:

1. High-voltage connection to battery

2. Drive motor-generator B; capable of 87 kW output

3. High-voltage connection to power electronics

4. Drive motor-generator A; capable of 48 kW output

5. Power Inverter Module


F08 module

Fig. 8


New 1.5L Range-Extending Engine


The 1.5L direct-injected 4-cylinder engine produces 101 horsepower at 5,600 rpm and uses regular unleaded gasoline. It features a coil-on-plug ignition, cooled exhaust gas recirculation and a variable displacement oil pump. (Fig. 9)


F09 1.5engine

Fig. 9

5ET50 Hybrid Transmission


The 5ET50 electronically-controlled, continuously-variable automatic transaxle features a torque dampener assembly with a rotating friction clutch, a stationary mechanical (one way) clutch, one stationary and one rotating friction clutch assembly, a hydraulic pressurization and control system, a power inverter (and control) module, an electric fluid pump, two planetary gear sets, and two electric drive motor-generators.


It has five modes of operation:

1. Single Motor Electric Vehicle (EV)

2. Dual Motor Electric Vehicle (EV)

3. Extended Range Low

4. Fixed Ratio Extended Range

5. Extended Range High


Some Volt models may experience unexpected engine flairs when the vehicle is at a steady speed or beginning to slow down. This is a normal operating characteristic of the drive unit as it moves through the five modes of operation, with the engine speed increasing to allow for the synchronous shifting that produces the engine’s maximum efficiency. Keeping the vehicle in Drive and using the brake pedal should reduce the number of engine flairs.


– Thanks to Sherman Dixon, Keith Newbury, Steve Falko and Chuck Wieseckel

2016 Volt High-Voltage Connectors

When attempting to remove or connect high-voltage connectors on the 2016 Volt, use care to avoid breaking any part of the connectors, which can be difficult to operate and prone to damage, if not handled properly.


For example, the PP2000 Axial connector (Fig. 10) — located between the T6 Power Inverter Module and the X3 connector of the Rechargeable Electric Energy Storage System (high-voltage battery pack) at the Volt’s Battery Bulkhead Disconnect Unit — can prove particularly challenging when reconnecting the cable after diagnostics and/or repairs.


F10 Volt connector

Fig. 10


TIP: Following is an example of how to remove and connect this connector. For details on other high-voltage connectors on the 2016 Volt, see Service Information Document 4283326.


Before working on any high voltage system, be sure to follow all high voltage safety procedures.


PP2000 Axial Disconnect Procedure


1. Pull the green Connector Position Assurance (CPA) tab back from the locked position to the pre-stage position. (Fig. 11) There will be an audible click sound when the tab is in the correct position.


F11 connector 1

Fig. 11


2. Depress the orange primary lock feature (tab) to release the lever.

3. Lift and rotate the lever to place the connector in the partial-mate position. Only rotate the lever until the secondary locks contact each other at the top of the connector. (Fig. 12)


F12 connector 2

Fig. 12


4. Depress the secondary connector lock. Keep the lock depressed and rotate the lever forward to the pre-stage position. There will be an audible click sound when the connector lock disengages. (Fig. 13)


F13 connector 3

Fig. 13


5 .Pull back on the female connector to disconnect the connector completely from the high voltage battery pack.


PP2000 Axial Connect Procedure


TIP: Using the connector lever to draw the connectors together during the pre-stage position may damage the connector lever pivots. The initial mating of the connector halves must be performed by hand without the use of the connector lever. Only use the lever to fully mate the connector halves when the lever has rotated beyond the pre-stage position.


Note: Ensure the lever and CPA tab are in the pre-stage position.

1. With the lever and CPA tab in the pre-stage position, align the connector with the index features and install the connector to the pre-locking position. The lever will be released from its pre-stage position with a short movement.

2. Pull the lever to the full-stage position. There will be a very audible click sound.

3. Push the green CPA tab to lock the connector in the full-stage position. There will be a very audible click sound when the connector is secured.


For a demonstration, check out the December broadcast of the Emerging Issues seminar that shows the removal and connection of the connector to the high-voltage battery pack. (Fig. 14)


F14 connector video image

 Fig 14

– Thanks to Joe Ciagala and Steve Falko



Twin Turbocharged V6 Engine Sounds

A noise condition may be heard on some 2014-2016 Cadillac models equipped with the twin turbocharged V6 engine (RPO LF3, LF4).


Cold Start Rattle Sound at Idle


On some 2014-2016 CTS-V Sport and XTS models equipped with the twin turbocharged 3.6L V6 engine (RPO LF3), a rattle sound may be heard coming from the turbocharger when the engine is cold. This is a cold start noise at idle.


Click below to listen to an example of the rattle sound. (Fig. 15)


F15 turbo sound when cold image

Fig 15


TIP: Do not confuse this noise with a similar noise heard when revving the engine.


If the rattle sound when cold is from the turbocharger, and the noise is unforced, there is a new turbocharger assembly available with a revised spring for the wastegate to limit movement when cold.


The new part numbers are 12666538 (turbocharger assembly – LH) and 12666539 (turbocharger assembly – RH) for the CTS-V Sport and 12666540 (turbocharger assembly – RH/LH) for the XTS. If the vehicle already has these part numbers installed, do not replace the part again.


Rattle Sound when Revving the Engine


A brief rattle or tick sound when revving the engine may be heard on some 2014-2016 CTS Sedan (VIN A) and XTS models equipped with the twin turbocharged 3.6L V6 engine (RPO LF3) and 2016 ATS-V models equipped with the twin turbocharged 3.6L V6 engine (RPO LF4).


This sound is heard when the vehicle is in Park or Neutral and can sometimes be heard at the beginning or end of vehicle acceleration while in Drive. The brief rattle sound is a normal characteristic of the vacuum actuated turbocharger. Do not replace the turbocharger assembly for this condition.


Click below for an example of this normal turbocharger sound. (Fig. 16)


F16 turbo sound when revving image

 Fig 16

– Thanks to Bryan Salisbury


Proper Battery Fuse Block Cover Removal

The battery fuse block cover assembly may be difficult to remove on 2015-2016 Colorado and Canyon models. If the cover is opened incorrectly, the hinge or latch may break.


To properly remove the battery fuse cover:


1. Unlock the small latch for the positive cable cover (Fig. 17) on the engine side of the battery cover assembly.


F17 small latch

Fig. 17


2. Next, lift the positive cable cover and unlock the main cover latch (Fig. 18) on the engine side of the assembly.


F18 cover latch

Fig. 18



3. Now, the front cover latch can be unlocked. (Fig. 19) Lift the hinge nearest the fender to access the battery and fuse block. (Fig. 20)


F19 main cover latch

Fig. 19


F20 cover open

Fig. 20


– Thanks to Charles Hensley

Fastener Appearance under the Hood

The two fasteners located on either side of the hood latch (Fig. 21) on the 2016 Camaro may appear to be loose. Upon inspection, these fasteners clearly show a gap between the head of the fastener and the plastic trim panel.


F21 fastener 1

Fig. 21


Do not attempt to tighten or otherwise move these two fasteners, even though they may appear to not be fully seated. These fasteners are part of the front fascia support bracket. The preset gap (Fig. 22) is by design and each fastener has Loctite applied to the threads so the preset gap does not change.


F22 fastener 2

Fig 22


This component arrives at the assembly plant preadjusted, so these fasteners are not adjusted when the component is installed in the car.


The two fasteners are adjustable to allow for hood to fascia alignment, but they should only be adjusted if the fascia is too high or too low in reference to the hood. When these fasteners are adjusted, the vertical clearance of the front fascia to hood gap will be changed.


– Thanks to Matt Bierlein

Poor Ground Connection at G110

On some 2009-2015 CTS-V models, several intermittent conditions may be present, including a Service Power Steering message, reduced power steering assist, and illuminated ABS, traction control and electronic stability control (StabiliTrak) warning lamps on the instrument cluster.


In addition, DTCs C0450 (Steering Assist Control Actuator Circuit), C0899 (Device Voltage Low), U0121 (Lost Communication with Electronic Brake Control Module), U0123 (Lost Communication with Yaw Rate Sensor Module), or U0126 (Lost Communication with Steering Wheel Angle Sensor Module) may be set.


If any of these conditions are found, check for an aftermarket Cold Air Intake (CAI) assembly installed on the vehicle. Certain aftermarket CAI manufacturers use Ground 110 (G110) (Fig. 23) as a bracket mounting point (Fig. 24), which causes a poor ground connection on the vehicle.


F23 G110

Fig. 23


F24 CAI bracket

Fig. 24


TIP: G110 should not be used to attach any aftermarket accessories.


Remove the Cold Air Intake (Fig. 25) and reevaluate the performance of the vehicle.



Fig. 25


– Thanks to David Antal

DTCs Set after Turbocharger Replacement

After installing a remanufactured turbocharger on a 2006-2010 Express, Kodiak, Silverado, Savana, TopKick or Sierra equipped with a 6.6L diesel engine (RPO LBZ, LLY or LMM), a Check Engine MIL and DTCs P003A (Turbocharger Boost Control Position Not Learned) and/or P2563 (Turbocharger Boost Control Position Sensor Performance) may set.


The DTC P003A/P2563 diagnostic must be completed. DTCs P003A and P2563 can set due to turbocharger vane control solenoid or vane position sensor concerns. After any service performed on the turbocharger or turbocharger components, a turbocharger relearn must be performed. Failure to perform the turbocharger learn procedure may cause other DTCs to set.


If the P003A/P2563 diagnostic is inconclusive or if the vane control solenoid and vane position sensor are tested with no trouble found, replace the turbocharger.


If these conditions were found after installing remanufactured turbocharger part number 19329915, replace it with new turbocharger part number 12639460.

If these conditions were found after installing remanufactured turbocharger part number 19329916, replace it with new turbocharger part number 98011735.


– Thanks to John Stempnik

The Next Generation Multiple Diagnostic Interface – The MDI 2

The next generation of the J2534 GM Multiple Diagnostic Interface, or MDI 2 (Fig. 1, right), offers increased processing power and security than the original MDI (Fig. 1, left) for faster programming speeds on current Global A vehicles as well as future Global B vehicles. The compact communication module is required in order to manage the transfer of data between a vehicle’s onboard network and a service technician’s PC.



Fig. 1


The EL-52100 MDI 2 is now available for purchase at the Special Service Tools website,, or by calling 1-800-GM-TOOLS.


The MDI 2 supports diagnostic applications — GDS 2, Data Bus Diagnostic Tool, and Tech2Win — as well as Pass-Thru programming applications — TIS2Web–SPS.


Enhancements to the tool were based on technicians’ feedback on how they use the MDI and how to improve it. It replaces the first generation MDI, introduced in 2007, for Pass-Thru programming on current GM models. The MDI 2 is backward compatible, so it can be used to perform Pass-Thru programming on all vehicles built since 1996.


The MDI 2 connects to the vehicle via the J1962 connector using a new DLC cable. Connection between the MDI 2 and the PC running the Global Diagnostic System 2 (GDS 2) software can be accomplished via standalone (USB), through a new Point-to-Point wireless Wi-Fi interface feature (a simple plug & play), or through the dealership network (Ethernet or wireless).


MDI 2 Kit


The EL-52100 MDI 2 kit includes:

  • MDI 2 Unit
  • SAE J1962 DLC Cable (Fig. 2)
  • 10-ft. USB A to USB B Cable (Fig. 3)
  • Ethernet Cable
  • D-Link Wireless USB Adapters (Dongles) (Optional; for wireless connection) (Fig. 4)


F02 MDI-2 dlc cable

Fig. 2


F03 MDI-2 usb cable

Fig. 3


F04 MDI-2 dongle

Fig. 4


A DLC Cable Self-Test Loopback Adapter (Fig. 5) was sent to dealerships as an essential tool in December. It’s compatible with the MDI and MDI 2. It’s also sold separately through GM Dealer Equipment.


The adapter is used to test the DLC cable for open wires when used with the MDI Manager software. The adapter also can be used to power the MDI or MDI 2 on the workbench.


F05 MDI-2 loopback

Fig. 5


MDI 2 connections (Fig. 6)

A. USB Port Type A

B. DB26 Connector (DLC Cable)

C. USB Port Type A

D. USB Port Type B – PC Connection Port

E. Wireless Adapter (Dongle)

F. Ethernet Port


F06 MDI-2 connections

Fig. 6


New Features


  • Wi-Fi Connection – The USB Wi-Fi adapter uses a USB dongle that enables Point-to-Point connections without the need for Wi-Fi SSID information or a wireless router.
  • USB Connection – Uses a new, more secure Type B connector and Ground Offset Failure protection. A wired connection is recommended for longer programming events.
  • Power Source – The MDI 2 is powered from the vehicle battery via the DLC Cable. It may also be powered over USB to perform firmware updates only using a PC.
  • Power Backup – Internal batteries that were used in case of a power interruption have been removed, which eliminates the possibility of old batteries corroding over time and damaging the unit. Capacitors maintain power during engine cranking, so operation is maintained.
  • Firmware Download – Uses USB 2.0 for faster firmware downloads instead of a separate AC power supply.
  • Future Expansion – Additional USB ports, an SD memory card slot and Function buttons are built into the unit for future enhancements.
  • Operating Temperature Range – The temperature range has been extended to -20° to 70°C (the MDI range was zero to 50° C).
  • DLC Cable – The DLC cable is twice as long as the previous cable and connects at the top, making it easier to use. The cable only connects to the MDI 2. A self-test adapter (accessed through the MDI Manager) can be used to test the integrity of the cable.


MDI Manager Software


The MDI Manager must be installed on the PC in order to configure, update and run diagnostic applications targeted for the PC.  Initially, use the MDI Manager software to set up the configuration of the MDI 2. The MDI Manager is also used to update the firmware on the MDI 2. Visit the TIS2Web/GlobalTIS website to determine if a newer version of MDI Manager software is available.


Wireless Dongle Setup


The first time the MDI 2 is used, the point-to-point USB dongle must be paired with the PC, which will install the necessary drivers on the computer. One dongle should be plugged into the PC and one into the MDI 2. (Fig. 7) The dongles are identical. Use either one for either connection. Remove the bottom dust cover to access the port.


TIP: Do not plug the dongle into a USB hub. It must be plugged directly into the computer.


F07 dongle connections

Fig. 7


Connect the MDI 2 to the PC via the USB cable. After starting the MDI Manager, the Point-to-Point connection is automatically configured. The USB dongles are intended to stay plugged into the PC or laptop at all time. If it must be removed, safety eject it by right-clicking on the Windows USB icon in the bottom right toolbar on the computer.


Dealerships considering new purchases should look into the MDI 2 for its many new advantages The original MDI will continue to be supported, but will not work on future Global B models.


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


– Thanks to Chris Henley

Switching to the MDI 2 on Your Computer

Switching from the MDI to the MDI 2 on your computer can be done easily by changing the Device Type on the PC. There are two different GDS 2 locations to change the Device Type — the Home screen (under Preferences) and the Vehicle Selection screen (by pressing the Select Device button).


Home Screen


1. Select Preferences on the GDS 2 Home screen. (Fig. 8)


F08 GDS 2 home screen preferences

Fig. 8


2. Under Preferences, select the Device Type tab and click the MDI 2 as the new device. (Fig. 9)


F09 GDS 2 device type screen

Fig. 9


Vehicle Selection Screen


1. Click the Select Device button on the GDS 2 Vehicle Selection screen. (Fig. 10)


F10 GDS 2 vehicle selection screen

Fig. 10


2. The Device Type screen will open. Click the MDI 2 as the new device.

3. After selecting the MDI 2 as the device, GDS 2 shows the Device Explorer screen, which should show the available MDI 2 devices. (Fig. 11) If this explorer screen only shows the MDI, not the MDI 2, click Cancel and then click Select Device to switch to the MDI 2.


F11 GDS 2 device explorer

Fig. 11


– Thanks to Chris Henley

MDI and MDI 2 DLC Cable Self-Test Adapter

A DLC Cable Self-Test Loopback Adapter (EL-47955-1) (Fig. 12) was sent to dealerships as an essential tool in December. The adapter is used to test the DLC cable for open wires when used with the MDI Manager software.


The adapter also can be used to power the MDI or MDI 2 on the workbench. When testing the DLC cable, it’s recommended to power with the 12V DC jack.


F12 MDI-2 loopback

Fig. 12




1. Plug the adapter into the DLC Cable and MDI/MDI 2.

2. Apply 12V to the adapter, either using the 12V DC jack or the vehicle DLC (does not test power and ground when powered by DLC). (Fig. 13)


F13 adapter connect

Fig. 13


3. Connect the MDI or MDI 2 to the PC using the USB cable.

4. Connect the MDI or MDI 2 to the MDI Manager software.

5. Select the Cable Test button (Fig. 14) from the HELP tab in the MDI Manager software.


F14 adapter test button

Fig. 14


TIP: Remove the adapter after testing. It should not be left on during normal diagnostics.


– Thanks to Chris Henley

TOP TIER Detergent Gasoline Update

TOP TIER Detergent Gasoline contains 2–3 times more detergent than the U.S. Environmental Protection Agency (EPA) and Canadian General Standards Board (CGSB) minimum requirement. TOP TIER gasoline was developed to meet the detergent standards set by General Motors, BMW, Honda, Toyota, Volkswagen, Audi and Mercedes-Benz. The added detergents result in a lower amount of intake valve deposits that can negatively affect fuel economy, emissions, and performance.


Additional gasoline retailers have been added to the TOP TIER list for gasolines meet the TOP TIER Detergent Gasoline Standards.


Benefits of TOP TIER Gasoline


All vehicles will benefit from using TOP TIER Detergent Gasoline over gasoline containing the “Lowest Additive Concentration” (LAC), which is the EPA and CGSB minimum detergent treat rate requirement. GM strongly recommends the use of TOP TIER Detergent Gasoline. Many gasoline retailers provide fuels with lower-quality additive packages that can build up deposits on fuel injectors and on intake valves. (Fig. 15) Fuel injectors that become restricted with carbon deposits over time result in an incorrect injector spray pattern. The deposits on intake valves reduce fuel economy by creating a porous surface that collects wet fuel, affecting the air to fuel mixture in the cylinder and releasing fuel late in the combustion cycle, which leads to increased unburnt hydrocarbon (HC) and carbon monoxide (CO) emissions.


F15 valve

Fig. 15


TOP TIER Retailers


TOP TIER is a voluntary program and not all fuel marketers offer TOP TIER Detergent Gasoline. Visit for TOP TIER retailers that meet the fuel standards in all octane grades as well as additional fuel information.


– Thanks to Tracy Lucas

UPDATE: No Start, Loss of Communication Conditions

Some 2015-2016 Colorado and Canyon models may have a condition of no crank/start, loss of communication, engine stall or an illuminated Service Engine Soon lamp with possible Driver Information Center messages. If any of these conditions are present, inspect the engine wiring harness for contact with the water pump pulley (Fig. 16), the oil filter housing (Fig. 17), and the engine boss near the left rear cylinder head (Fig. 18) behind the coolant pipe.


Repair the engine harness as necessary and route it away from these possible contact points.


F16 water pump pulley

Fig. 16


F17 oil filter housing

Fig. 17


F18 engine boss

Fig. 18


– Thanks to Ken Cole

Connector Corrosion Conditions

Some 2010-2012 LaCrosse and 2011-2012 Regal models may have possible corrosion and/or water and dirt intrusion at connector X403 (LaCrosse) or X350 (Regal), resulting in an intermittent Service Engine Soon lamp and possible engine stalling while driving.


Remove the appropriate rear wheel well liner and inspect for water/dirt intrusion or corrosion at the connector. (Fig. 19) If these conditions are found, replace both the male and female connectors and pack the connector with dielectric grease.


F19 connector

Fig. 19


– Thanks to Chris Hightower

Loss of Power Steering Assist

A loss of power steering assist may occur on some 2015–2016 Colorado and Canyon models. A Service Power Steering message may be displayed on the Driver Information Center and data communication DTCs U0073 (Control Module Communication Bus Off), U0102 (Lost Communication with Transfer Case Control Module), U0109 (Lost Communication with Chassis Control Module) and/or U0140 (Lost Communication with Body Control Module) may be set.


Inspect the terminals for circuits 2500 and 2501 at the Transfer Case Control Module (TCCM) connector (Fig. 20) and X103 (chassis harness to power steering harness) (Fig. 21) and X106 (body harness to chassis harness) (Fig. 22) for oversized or bent terminals. Repair the connectors as needed.


F20 tccm 2500 2501

Fig. 20


F21 x103

Fig. 21


F22 x106

Fig. 22


– Thanks to Ken Cole

Backup Camera Display after Shifting out of Reverse

Drivers of some 2015-2016 Colorado and Canyon models equipped with radio RPO IO3 may notice that the Rear Vision Camera (backup camera) image (Fig. 23) may remain on in the radio display for a few seconds after shifting out of Reverse. On vehicles equipped with a manual transmission, the screen may turn blue for a few seconds after shifting into a forward gear before returning to the radio display.


These conditions are a normal function of the Rear Vision Camera and no repairs should be made.


F23 camera display

Fig. 23


The Rear Vision Camera is designed to automatically show the image behind the vehicle on the radio screen when the transmission is shifted into Reverse. The radio screen should return to the previous screen after approximately four seconds once the vehicle is shifted out of R (Reverse).


– Thanks to Ken Cole

Service Know-How

10216.01V – Emerging Issues

January 14, 2016


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

Bulletin Review – December 2015

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Screen Shot 2016-01-15 at 10.11.18 AM

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