January 2010 Archives

The pick-up box of the 2007-2010 Silverado and Sierra was designed for the use of add-on equipment. However, there are specific mounting points that must be used along with maximum weight restrictions.

Structural members have been added to provide load paths directly to the platform cross-sills and into the vehicle frame. (Fig. 1, A) Aftermarket accessories should take advantage of these intended load paths. Depending on the accessory design, it may be necessary to add some form of a spacer under the toolbox at the structural hard points to take up any gap.

TIP: The GM Cargo Management Option mounting points should not be used for attaching aftermarket equipment. (Fig. 2) They are intended for use with the GM Cargo Management system equipment only, as shown in the photo. (Fig. 3)

When carrying removable items, it may necessary to put a limit on how many passengers are carried inside the vehicle. Be sure to weigh the vehicle before installing new equipment. Do not exceed the Gross Axle Weight Rating (GAWR) of the front or rear axle.

For more details on the load bearing structural guidelines, refer to the Body Builder Manuals at www.gmupfitter.com.

- Thanks to Bernard Lackey

A change to the locking tab on the Data Link Connector (DLC) used on the 2009-2010 Vibe may cause the MDI cable to get stuck or be difficult to remove after connecting it to the vehicle.

There are three versions of the MDI cable, depending on when the MDI was purchased. The affected cable is black and does not have a covered locking tab. (Fig. 4) Refer to PI0008 in SI for more information to help you determine which version you have.

If you have the affected version of MDI cable, the connector end should be modified using the procedure outlined in PI0008, which includes before and after photos of the modified cable.

- Thanks to Matt Singer

Generally, driveability issues and engine operation conditions can be diagnosed using standard SI procedures, diagnostic tables and diagnostic tools. However, there is the occasional condition that cannot be satisfactorily addressed or corrected this way.

In cases like these, consider whether the vehicle has been equipped with non-OEM components or service parts. Because these aftermarket components were not developed, engineered and tested along with the vehicle they are installed in, they may not perform in the same way as the OEM part that was replaced. Two such cases have recently been identified and are summarized here.

Misfire with No Apparent Cause

This information applies to:

2004-07 ION Redline

2005-07 Cobalt SS

with 2.0L Supercharged Engine (RPO LSJ).

2007-09 Solstice GXP and SKY Redline

2008-10 Cobalt SS and HHR SS

with 2.0L Turbocharged Engine (RPO LNF).

A vehicle may illuminate a MIL with DTCs P0300, P0301, P0302 or P0304. The root cause typically cannot be determined. The misfire condition usually occurs with extended idling and may be reduced or eliminated by raising the RPM slightly or inducing an engine load (such as the A/C).

Engineering has determined that aftermarket parts (such as a light-weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Whenever any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this condition. When diagnosing a misfire DTC and no condition can be found following SI procedures, inspect for installed aftermarket components.

Driveability Issues Related to Aftermarket Air Filters

Bulletin #04-07-30-013B addresses driveablilty issues in all GM cars and trucks. Some owners may install an aftermarket reusable air filter into their vehicle and then experience driveability issues, automatic transmission shift issues and/or an illuminated SES light.

The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the following conditions may occur.

-      Service Engine Soon (SES) light on

-      Transmission shift conditions, slipping and damaged clutch(es) or band(s)

-      Engine driveability conditions, poor acceleration from a stop, limited engine RPM range

To verify the condition, compare the MAF GPS reading with the reading of a like vehicle that has an OEM air box and filter under the same driving conditions.

If a vehicle is encountered with these conditions, check for a reusable aftermarket over-oiled air filter. If an aftermarket reusable air filter is used, inspect the MAF sensor element and the air induction hose for contamination of oil before making any warranty repairs.

DO NOT repair MAF sensors under warranty if concerns result from the use of an excessively/over-oiled aftermarket reusable air filter.

TIP: The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty.

TIP: Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, over-oiled air filter are not considered to be warrantable repair items.

The other extreme is the UNDER-oiled air filter, which can also cause driveability concerns. The typical oiled aftermarket air filter requires cleaning and re-oiling at regular intervals to maintain optimum filtering. Failure to do so eventually allows fine debris to pass through the filter. A buildup of debris on the MAF sensor reduces the sensor's ability to correctly detect airflow, leading to driveability concerns.

- Thanks to Jeff Gorenflo and Dave Peacy

Some owners of a 2009 Cadillac SRX with the power liftgate option (RPO E61) may comment that the power liftgate will partially open, then reverse direction and return to the closed position. Lower ambient temperatures may aggravate this condition.

This liftgate reversal condition may be caused by the system detecting a false obstacle during the first 12 inches (305 mm) of travel, which will cause the liftgate to reverse direction and return to the closed position.

TIP: Do not service or replace the liftgate module, struts, actuators or latches.

A revised calibration has been developed to address this false reversal condition. Reprogram the power liftgate module using TIS2WEB and selecting "Power Liftgate Module Reprogram." Refer to SI for more information.

- Thanks to Doug Daugherty

Engines should not be idled to maintain a battery charge unless sufficient fuel has been added to the fuel tank to comfortably assure the vehicle will not run out of fuel during the idling period. The engine in many vehicles will continue to run in a low or no fuel condition for a significant period of time, which can result in damage to the fuel pump due to the lack of fuel to cool the pump.

It is strongly suggested that the batteries of vehicles in dealership inventory be maintained with a battery charger whenever possible.

Idling a vehicle is very inefficient because of the ability of the generator to charge the battery is very limited at idle speed. It's much faster and much more effective to use a battery charger to maintain a vehicle's battery. Comparatively, the cost of charging a battery using gasoline or diesel fuel is significantly higher than using electricity from a wall outlet.

- Thanks to David MacGillis and Len Tillard

The power driver's seat on the 2010 LaCrosse, SRX, Equinox and Terrain includes a memory function that enables occupants to set and recall the desired position of the seat that works differently than past GM models. Some customers may not be aware of the proper operation of the memory seat functions and may bring their vehicle in for service.

Memory Positions

The seat memory buttons or the Remote Keyless Entry transmitters (key fobs) can be used to save and recall memory positions for the driver's seat and outside rearview mirrors as well as the adjustable pedals and power tilt/telescoping steering column (if equipped).

Two unique memory positions can be saved using the seat memory buttons by, after making the desired adjustments, simultaneously pressing and holding the MEM button and button 1 or 2 on the seat until a beep sounds.

In addition, three unique memory positions can be saved using key fob 1 (ID 1), key fob 2 (ID 2), and all additional key fobs 3 through 8 (ID 3).

TIP: The key fob memory positions are not tied to the memory seat recall buttons, so there is no direct correlation between key fob 1 and memory button 1 or key fob 2 and memory button 2. The memory positions for key fob 1 and memory button 1 will be the same only if the seat, mirrors, adjustable pedals and steering column were at the same position as memory button 1 when the ignition was last turned off

To save memory positions to each key fob, press Unlock on the desired key fob, turn on the ignition, make the desired adjustments, and then turn off the ignition.

Each time the ignition is turned off, the memory seat module will save the current position of all seat, mirror, adjustable pedal and steering column positions for the current key fob number.

Memory Recall Operation

Memory recall is a supervised operation. Ground from the seat memory control module is supplied at all times to the driver seat memory switch. Depending on input, the seat memory control module commands the appropriate seat motors to move to the preset seat position saved in memory.

To recall the memory position, press and hold button 1 or 2 on the outboard side of the seat until the memory position is reached. Releasing the button before the stored memory position is reached cancels the recall.

The memory positions also can be programmed using the Vehicle Settings menu on the audio system to be recalled automatically according to the key fob used to unlock the vehicle's doors.

If a vehicle is brought to the dealership with this condition, no repairs are necessary. Explain to the customer the proper operation of the memory seat recall function.

- Thanks to Eric Kenar and Joe Lancour

On some 2008-2010 Express and Savana models, it may be difficult to adjust or change a setting on the HVAC control due to a broken HVAC control head knob. (Fig. 6)

When replacing an HVAC control knob, all HVAC control knobs should be replaced. A vehicle could have up to three HVAC control heads with up to nine HVAC control knobs, depending on the option content of the van.

The replacement knobs are available in a pack of three.

Do not replace the entire HVAC control assembly for this condition.

- Thanks to Calvin Williams

On some 2010 LaCrosse, SRX, Equinox and Terrain models, the following conditions may be present: no GPS signal to the navigation radio, the No GPS symbol is active, or the clock cannot be set. No DTCs will be set for these conditions. The GPS signal to the VCIM is present and can be verified by OnStar.

If OnStar GPS is also inoperative/incorrect, follow the appropriate SI diagnostic procedures.

The possible cause for these conditions may be that the blue coax cable connectors 1 and 2 are in the wrong location. Though the splitter location is slightly different in the affected models, the blue connectors of the GPS Antenna and GPS Splitter are identical, enabling the possibility that the GPS Antenna could be directly connected to the OnStar module and allow the GPS Splitter to be connected to itself.

Refer to SI for the specific location of the GPS splitter for the SRX, Equinox and Terrain (Fig. 7) and the LaCrosse (Fig. 8).

- Thanks to Jeremy Richardson

The Remote Keyless Entry (RKE) and/or Remote Vehicle Start (RVS) range may be poor on some 2008-2010 Chevrolet Impala models.

If this condition is present, remove the driver's side A-pillar trim to check if the RKE/RVS coax antenna is in the position seen in the accompanying illustration. (Fig. 9)

If the coax antenna is in the incorrect position above the bolt head, follow these steps:

1)    Cut an approximately 1-inch piece of electrical tape

2)    Locate the two plastic clips near the instrument panel that attach the coax antenna to the A-pillar sheet metal

3)    Pull down the antenna between the two clips so that the antenna is routed on top of the metal clip bolted to the A pillar. If possible, pull it under the bolt head that secures the metal clip to the A pillar. (Fig. 10)

4)    Apply the piece of tape over the coax and the clip so the antenna stays in position. (Fig. 11)

5)    Reattach the A-pillar and activate a button on the Key FOB to confirm functionality.

Also check the battery in the transmitter if range is poor.

TIP: Weather and the physical environmental also may limit the range of the RKE/RVS system. Compare the range of the RKE/RVS with a similar vehicle.

- Thanks to David Eplin

The power steering on a 2007-2010 Impala may exhibit a whine or growl noise.

The Impala power steering pump has a pressurized cap with a two-way valve designed to control the air pressure inside the reservoir. As the system temperature increases during normal vehicle operation, the power steering fluid will expand and compress the air inside the reservoir. At certain air pressure the cap valve will open to allow the air to escape through the cap.

When the vehicle is stopped and system temperature is decreasing, the power steering fluid will contract, resulting in a negative pressure inside the reservoir. This will cause the valve to open and allow outside air to enter the reservoir.

To address the pump noise condition, the air bubbles need to be thoroughly removed from the power steering fluid in the power steering hoses and pipes.

Do not replace the power steering pump or rack/gear for the whine noise.

Follow this procedure to fill and bleed the power steering system using the MityVac vacuum tool (or equivalent):

TIP: The fluid level must be maintained throughout the bleed procedure.

1.     Fill the fluid reservoir to the FULL COLD level. Leave the cap off.

2.     Raise the front wheel off the ground.

3.     Attach the J 43485 (adapter) to the J 23738 (Mityvac), or equivalent. Place the J 43485 on/in the pump reservoir filler neck. Apply a vacuum of 20 in. Hg maximum.

If the J 43485 (adapter) is not available, an equivalent can be made using a rubber seal/stopper and brass fitting.

4.     An assistant is needed for this step. Apply vacuum while turning the steering wheel lock-to-lock. Maintain 20 in. Hg while turning. Using a clear line will allow you to see the bubbles evacuating system. Stop when no more bubbles are seen.

5.     Wait five minutes. Typical vacuum drop is 2-3 in. Hg. Verify the fluid level. If the fluid level is low, fill to the full line.

6.     Reinstall the cap. Start and idle the engine.

7.     Turn the engine off. Verify the fluid level. If the fluid level drops, add fluid. Repeat Steps 4 and 5 until the fluid level stabilizes.

8.     Start and idle the engine. Turn the steering wheel 180 degrees in both directions five times. DO NOT TURN LOCK-TO-LOCK.

9.     Turn off the ignition. Verify the fluid level.

10.  Install the cap. The bleed procedure is complete.

- Thanks to David Eplin

Owners of a 2005-2009 LaCrosse (Allure in Canada) may comment that the battery may go dead if the vehicle sits for five days or more. When inspecting the vehicle, an approximately 200 ma draw may be noticed that goes away when removing both of the CHMSL and HAZRD fuses, or the BCM connector X1/C1. This applies to vehicles with the factory garage door opener on the driver's sun visor.

Do not replace the BCM for this condition.

The battery draw may be due to owners clipping their personal garage door opener over the top of the factory garage door opener on the sun visor. Remove the owner's garage door opener and check if the draw goes away. Point out a better location for the owner's garage door opener.

- Thanks to David Eplin

DTC P0016 or P0017 may set after resetting the timing following service on the 2010 Equinox and Terrain with the 2.4L engine (RPO LAF); 2008-2010 Cobalt SS, HHR SS and 2007-2009 Solstice GXP, SKY Redline with the 2.0L engine (RPO LNF).

On Ecotec 4-cylinder engines (RPO LNF/LAF) with SIDI-direct injection the lower timing chain crank gear has a spacing washer installed in front of (and behind) the lower timing chain crank gear. This spacer/washer obscures or covers the correct timing mark.

The outer spacer/washer is between the crank/balancer pulley and the lower timing gear and may remain in place when the pulley is removed. The spacer/washer has a dot/mark on its surface that may be mistaken for the lower timing mark, which may cause the engine to be timed incorrectly although all the timing marks appear to line up.

This may lead to cam correlation DTCs setting (such as P0016 or P0017). The outer spacer/washer must be removed when timing engine RPO LNF or LAF to view the correct timing mark on the lower crank gear. Additionally, earlier versions of EPC and SI may not show the washer as present on the 2.0L SIDI engine RPO LNF.

- Thanks to Jeff Gorenflo

A creak, pop or clunk noise may be heard coming from the rear of a 2006-2010 Impala after bulletin #07-03-09-001 has been performed. If the conditions described in the bulletin are not resolved after cutting off the four lower tabs of the rubber isolator and lubricating the isolator, then perform the following procedure.

Drive the vehicle to verify the creak/pop/clunk noise is still present. If the noise is present, disconnect BOTH rear stabilizer links. Make sure that the disconnected stabilizer links do not interfere with other suspension components or the body, and drive the vehicle again.

If the noise is gone, replace the stabilizer bar bushings and clean the stabilizer bar and its corresponding pockets. It is important to clean all debris and lubricants from the stabilizer bar and its corresponding pockets.

Install non-lubricated stabilizer bar bushings should the bushing need replacement.

TIP: Disconnect BOTH stabilizer links during diagnosis. Failure to disconnect both stabilizer links at the same time is likely to result in misdiagnosis and unnecessary replacement of the strut/coil.

- Thanks to David Eplin

On the 2010 Camaro, LaCrosse, SRX, Equinox and Terrain equipped with the base radio and PDIM/USB port, static noise may be heard when using the USB port to play audio from a portable device.

Verify that song data/information is still displayed (song track, title, artist, genre, etc.). Also verify that a portable device can play audio correctly through the 3.5mm input jack.

If the vehicle displays song data and has clear audio when using the 3.5mm input jack, replace the MPIM following SI procedures.

- Thanks to Jeremy D. Richardson

On some 2009 Enclave, Traverse, Acadia and OUTLOOK models, the ignition coil circuit connections may cause engine misfires that may lead to repeat catalytic converter failure as well as scoring of the cylinder bores.

Check the X3 connector, pin 51 - circuit 5291 for odd cylinders and the X3 connector, pin 47 - circuit 5292 for the even bank of cylinders. Pin drag the connections. If a concern is found, replace the terminals.

- Thanks to Ronald Mitchell

Some 2008-2009 Cadillac Escalade models and Avalanche, Tahoe, Suburban, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL models with RPO Z55 or Z95 may have a Service Suspension System message on the DIC and an incorrect rear suspension ride height. When checking for DTCs, the Electronic Suspension Control (ESC) module will have DTC C0696 or C0711 set.

This condition may be caused by the wiring to the Automatic Level Control (ALC) pressure sensor being shorted to ground. (Fig. 12)

TIP: The air compressor assembly may need to be removed from the vehicle to determine if the wiring is possibly pinched between the compressor assembly and frame.

Do not replace the complete air compressor assembly for this condition. Repair any damaged or shorted circuits and then reposition the wiring so it does not get damaged during the compressor assembly installation.

- Thanks to James Will

Some 2010 Enclave, Lacrosse, SRX, Equinox, Malibu, Traverse, Acadia or Terrain models equipped with the 6T70/75 automatic transmission (RPO MH2, MH4, MH6, MY9) built from June through September 2009 (use GMVIS to verify vehicle build date) may have no transmission engagement, or a delayed engagement, into Reverse or Drive, or transmission slip at low engine speeds. A line pressure test may show low line pressure at idle.

This condition may be caused by a damaged pump fluid outlet seal assembly.

Symptoms of this seal being damaged include:

·       Delayed engagement into Reverse or Drive until engine speed is raised to approximately 1,200-1,500 RPM.

·       Slipping forward or reverse gears at engine speed below approximately 1,200-1,500 RPM.

·       Low line pressure at idle. Line pressure should be checked as detailed in the Service Information.

·       Fluid streaming out of the pressure test hole when the fluid pressure test hole plug is removed and the engine is not running. Typically, when the plug is removed, a small amount of fluid will come out and then stop. With a damaged pump seal, fluid will continue to stream out similar to how engine oil runs out of the drain plug.

- Thanks to Ronald Mitchell

Some 2009-2010 Traverse models may have an intermittent no crank/no start condition. There may also be an inoperative radio condition and/or the IPC may be inoperative or erratic intermittently. During diagnosis, many low-speed communications codes may be found.

These conditions may be caused by a short-to-ground on circuit 5060 on the front passenger seat frame. These conditions are more evident when the front passenger seat is occupied.

Check circuit 5060 (dark green wire) being shorted on the front passenger seat frame. (Fig. 13) Repair the wire as necessary and reposition it to prevent any further chaffing.

- Thanks to Ron Erman

Some owners of a 2010 LaCrosse, Camaro, Equinox and Terrain may bring their vehicle to the dealership after service has been performed with inoperative cruise control and inoperative brake lights or the brake lights may not turn on with a light brake apply.

DTC C0277 may be set with symptom code 4B, Brake Pedal Position (BPP) Sensor Circuit Calibration Not Learned. If the BPP sensor is not calibrated, it may take more brake pedal travel to turn on the brake lights, and the cruise control will be inoperative.

TIP: Vehicles that have DTC C0277 4B set often have recently had the BCM replaced or reprogrammed. Anytime the BCM is programmed, it is necessary to relearn the BPP sensor.

Do not replace the cruise control switch or the BPP sensor if DTC C0277 4B is set. If these conditions are present, recalibrate the BPP sensor.

There are two different methods to perform the BPP sensor calibration.

Method 1 - Use the MDI tool and Service Programming System (SPS) on the TIS terminal

1.     Connect the MDI tool and access SPS on the TIS terminal

2.     Build the vehicle on SPS

3.     Select BCM Setup and follow the instructions

Method 2 - Use the MDI tool and GDS software

1.     Connect the MDI tool and access the GDS software

2.     Build the vehicle using the GDS software

3.     Select Module Diagnosis

4.     Select Body Control Module

5.     Select Configuration/Reset Functions

6.     Select Brake Pedal Position Sensor Learn

- Thanks to Ron Erman

10210.01D - Emerging Issues

January 14, 2009

To view Emerging Issues seminars:

Log in to www.gmtraining.com, select Service Know-How/TECHAssist from the menu, select Emerging Issues, and then Searchable Streaming Video to choose the current Emerging Issues seminar or past programs.