November 2009 Archives

Dealership personnel are not to remove and/or reposition head restraints (head rests) backwards in the front seat for any reason. Nor is the head restraint to be altered in any manner from the "as received" design. The position of the head restraint is required by law. Repositioning the head restraint backward may render the vehicle noncompliant with Federal Motor Vehicle Safety Standards.

Customers should be advised not to remove the head restraints. The head restraint is part of the seat system that is designed for occupant protection during a crash event. The seat works together with the head restraint to help protect occupants from head and neck injury.

Models that have these design requirements include 2009-10 Impala, CTS, Acadia, Traverse, Enclave, and 2010 LaCrosse.

Customers should be advised to change the seatback recline angle as little as necessary to achieve a more comfortable position while ensuring the seating position and the head restraint height is positioned appropriately as described in the owner manual.

Rear seat head restraints also should not be removed or repositioned unless the ability to do so is described in the owner manual.

- Thanks to Jeanne Barrett

With a combination of mechanical, aerodynamic and mass-reducing enhancements, the XFE models of the Silverado, Sierra, Tahoe and Yukon introduced in 2009 provide best-in-class fuel economy without any sacrifice in capability. (Fig. 1)

In 2010, the XFE pickups deliver even better fuel economy with an increased EPA highway rating of 22 mpg and a city rating of 15 mpg. XFE models of the full-size sport utilities will no longer be produced.

The Silverado and Sierra XFE models continue to be offered in 2WD crew cab body styles only. All models carry the XFE badge and are available with most regular production options. (Fig. 2)

2010 XFE Pickups

To reach their segment-leading fuel economy ratings -- a 7 percent improvement in city mileage and a 5 percent improvement in highway mileage -- the XFE trucks feature a number of differences from the regular full-size pickups.

All XFE models (2010 pickups as well as 2009 pickups and SUVs) are equipped with the 5.3L FlexFuel V8 engine (RPO LC9) with aluminum cylinder block and heads and the Hydra-Matic 6L80 6 speed automatic transmission (RPO MYC).

The efficiency of the Vortec 5.3L V8 is enhanced through the use of Active Fuel Management technology (AFM), which temporarily deactivates four of the engine's cylinders under light load conditions to help increase fuel economy approximately 6 percent. The LC9 engine also uses Variable Valve Timing to optimize the camshaft position for all driving modes. (Fig. 3)

For 2010, the pickups increase the use of the Active Fuel Management system, enabling the engine to run on four cylinders at cruising speeds more of the time. The additional engine management system enhancements do not affect payload, horsepower, or tow ratings.

Other XFE Enhancements

Other fuel-saving enhancements that were introduced on the 2009 models and continue for 2010 include lowered suspension and revised chassis tuning front and rear on all models, and a soft tonneau cover and extended front lower air dam on Silverado and Sierra, to help make the XFE models the most aerodynamic full-size pickups and SUVs in the industry.

XFE models also have a low 3.08 axle ratio and low rolling resistance tires to help increase fuel efficiency.

Mass is reduced with the use of aluminum lower control arms, aluminum spare wheel, and lightweight aluminum wheels (17-inch wheels on the 2009-2010 pickups and 18-inch wheels on the 2009 SUVs).

- Thanks to Jack Woodward

(Fig. 4)

The new Global Architecture (Global A)-based 2010 vehicles -- Camaro, Equinox, Terrain, SRX and LaCrosse -- can be programmed using SPS (Service Programming System). The same programming procedures should be followed as when programming other vehicles using SPS.

For diagnosis, Global A vehicles require the use of the new GM Global Diagnostic System (GDS) and the Multiple Diagnostic Interface (MDI) tool. These vehicles do not permit Tech 2^® communication for diagnostic purposes. For control module programming on Global A vehicles, GDS also offers a programming function, however, SPS with a hard wire connection provides a more stable programming environment.

During the programming process on Global A vehicles:

·       The programming is sequential, meaning that multiple control modules will be updated at the same time to prevent any conflicts that could result due to modules having incompatible versions of programming.

·       Several modules will have a setup procedure to relearn the values of vehicle systems and components.

·       Several modules require a configuration procedure that sets a security code configuring the control module to the specific vehicle, which helps prevent theft of the module.

TIP: If these modules are not configured to the vehicle, some will be locked immediately, while others will operate initially and then lock up after multiple key cycles.

·       During key fob -- Remote Keyless Entry and Remote Keyless Access (push-button start) -- programming on the SRX and LaCrosse, place the key fob in the pocket or molded recess that is used when the key fob batteries are weak. Placing the key fob in the pocket or recess, located at the bottom of the center console (SRX) or under the cupholder (LaCrosse), ensures optimum connectivity with the module during programming.

GDS and SPS

The accompanying chart provides a comparison of when to use GDS and when to use SPS when servicing a Global A vehicle.

Technicians that install LPO dealer-installed 20- or 22-inch accessory wheels on a full-size utility or pickup must perform several procedures in order for all vehicle systems to operate properly. (Fig. 5)

Following is a summary of the steps required when installing the 20- or 22-inch accessory wheels on certain 2009 Escalade, Escalade ESV, Escalade EXT, Avalanche, Silverado, Suburban and Tahoe (1500 series only), Sierra, Yukon, Yukon Denali, Yukon XL and Yukon Denali XL (1500 series only) models.

The RPO codes for the 20- or 22-inch accessory wheels that can be dealer-installed are: VSA, VSB, VSC, VSF, VS3, VZJ, VZK, VS5, VS4, VSJ, VSK, VZH, VSN and VS8.

RPO RPP designates the 17-inch wheel and tire that will be removed by the technician.

Vehicles built with RPO RPP always require the following service procedures:

1.         Install the new LPO accessory tire/wheel assemblies on the vehicle.

2.         Reprogram the control modules for the new tire/wheel size (steps 2.1, 2.2 and 2.3 must be completed in order).

2.1.     Contact TCSC at 1-800-828-6860 (English) or 1-800-503-3222 (French) to set-up the calibration database for the new tire size.

2.2.     Reprogram the EBCM (Electronic Brake Control Module). Use Tech 2^® pass-through programming in the Service Programming System (SPS).

2.3.     Reprogram the ECM (Engine Control Module). Use Tech 2^® pass-through programming in the Service Programming System (SPS).

3.         Reset the tire type and pressure.

3.1.     Use the Tech 2^® to perform a module set-up for the RCDLR (Remote Control Door Lock Receiver); go to Tire Type/Pressure Selection.

3.2.     Select the correct tire type (P-metric), and select the new tire pressure based on the new tire placard included with the accessory wheels.

4.         Learn the new Tire Pressure Monitor (TPM) sensors to the vehicle.

5.         Install the new tire placard included with the accessory wheels.

6.         Set the inflation pressure of each tire according to the new placard value.

For additional information about this process, please refer to Bulletin #06-03-10-001F (SUV) or #06-03-10-011E (Pickup).

GM accessory wheels are validated and released for specific vehicle applications. Warranty coverage and dealer indemnification will not be provided in situations relating to incorrect application usage or failure to perform required service procedures.

- Thanks to Loren Rusk

The windshield pillar garnish molding may be loose, leaving a gap at the top of the molding on the driver and/or passenger side, after service has been performed on the 2006-09 G6, AURA; 2006-10 Malibu, DTS; 2008-09 VUE; 2008-10 CTS, Express, Savana; 2010 Camaro, Equinox, Terrain, and LaCrosse.

This condition may be caused by the retaining clip (tether) not fully engaging after being removed for service. (Fig. 6)

Replace the retaining clip if this condition is present. The clip is available as a service part. (Fig. 7)

Do not replace the windshield garnish molding assembly if it is not affected.

TIP: Any time the windshield pillar garnish molding is removed, install new retaining clips. Do not re-use the old retaining clips.

Refer to Bulletin #09-08-110-008 and the appropriate Service Information for more information about replacing the retaining clip on the windshield pillar garnish molding.

- Thanks to Chuck Wieseckel

Dealership personnel are not to remove any labels from the sun visor of a vehicle for any reason. These labels are required by law.

Customers should be advised not to remove the sun visor labels. Once a label is removed, a permanent glue mark will remain. (Fig. 8)

Replacement labels are not available separately. If the label is removed, the entire sun visor must be replaced and is not covered under warranty.

- Thanks to Chuck Wieseckel

This information applies to the following vehicles:

·       2006-2010 HHR

·       2005-2010 Cobalt

·       2004-2010 Malibu

·       2008 Malibu Classic

·       2007-2009 AURA

·       2005-2009 G6

·       2006-2009 Solstice

·       2007-2009 SKY

Many electrical functions on these vehicles do not directly involve the Body Control Module (BCM), even though they may on other vehicles. The cooling fans, for example, are controlled by the ECM on the Malibu, but are controlled by the BCM on the Impala. The BCM is only a gateway between the high- and low-speed GMLAN serial data buses on the above listed vehicles.

Functions That Do Not Involve the BCM

The following list of features and functions are not controlled or dependent on the BCM. The BCM should NOT be replaced for conditions in these areas:

·       Cooling fans

·       Clock display

·       Radio display

·       Power mirrors

·       OnStar

·       Rear wiper (on Malibu Maxx)

·       Warning lamps (Telltale lights)

·       MIL (Service Engine Soon light)

·       Driver seat belt reminder light and chime

·       Power windows

TIP: The BCM also acts as a power distribution center and may provide a fused battery feed to the modules that actually do control these functions.

Do not assume a similar control module issue will apply to different vehicle lines. Refer to the appropriate Service Information for the proper diagnostic information.

- Thanks to Alexander Ballios and Marty Case

On the 2010 LaCrosse, SRX, Camaro, Equinox and Terrain equipped with the AM/FM radio/CD audio system (RPO UYE), the audio system may display some menus in a different language or some menu selections may be blank. This may cause the driver to not be able to set or change the clock, pair a Bluetooth phone, configure the vehicle, and/or change Tone/EQ settings.

These conditions may occur after experiencing a no crank or dead battery concern in which the language selections can be lost; or drivers may accidentally set the language to something other than their known language.

If any of these conditions are present, verify that the display is not completely blank. The following features will still display: clock, HVAC inside and outside temperatures, icons, scroll bars, reverse highlight cursor position and other graphical elements. In addition, RDS information, CD text and MP3 CD disc information will still be displayed.

To verify the condition is current, turn on the radio and confirm there is text shown under the antenna icon on the left and in the small folder icon on the bottom right. If both of these are blank, the issue is present and the following procedure should be used to reset the radio. If there is AM, FM or XM under the antenna icon and FAV (#) in the folder icon, the condition is not present and no further action is required as the radio has already reset.

To correct the condition, clear the radio memory by removing the radio fuse powering the radio for one minute. The radio will revert back to English as the language and all menus will be populated. Turn off the vehicle and open the door to allow the radio to turn off fully and store the new setting.

TIP: The radio fuse position is different for each vehicle. Refer to the Service Information to identify the fuse powering the radio itself, not the radio display. There is a display, or faceplate, fuse and if it is removed it will only turn off the display. Upon reinstalling the display fuse, the radio will remain powered up and the condition will still be present.

Updated software will be released to address this condition.

- Thanks to Jeremy Richardson

The 2010 SRX uses new silicon exhaust isolators that perform better with higher exhaust temperatures. The new silicon isolators take the place of more commonly used EPDM rubber isolators found on most vehicles.

The silicon isolators are softer than traditional rubber isolators and are more susceptible to tears during removal. When removal of a silicon isolator is necessary, use an isolator removal tool to prevent tears, nicks, or other damage. (Fig. 9)

TIP: Do NOT use a screwdriver or pry bar to remove a silicon isolator. Removal of all exhaust isolators -- silicon and rubber -- should be done carefully using the appropriate tool to avoid damaging the isolator. (Fig. 10)

If a silicon isolator shows any signs of damage, it should be replaced. A small tear could spread and lead to a complete separation of the isolator, which would no longer support the exhaust system. (Fig. 11)

- Thanks to Paul Lukasik

A Service Park Assist Message may be displayed on the DIC and/or the LED indicators at the right rear pillar may stay on or be inoperative on some 2007-2009 Silverado and Sierra models equipped with the Ultrasonic Rear Parking Assist system (RPO UD7).

This condition may be caused by the wiring harness to the LED indicators being pinched under a ground eyelet at the right rear pillar. (Fig. 12)

Remove the pinched harness from under the ground eyelet to repair the damaged circuits.

- Thanks to James Will

A technician may find DTC P2261, Turbocharger Bypass Valve Stuck Closed, set with no trouble found on some 2008-2009 Cobalt SS and HHR SS models. It may be intermittent in nature or the DTC may set after hard acceleration, usually in third gear. DTC P2261 is a Type B DTC and will not set on the first drive cycle, therefore, multiple test drives should be performed to confirm repair.

SI diagnostics for this DTC states that the ECM compared the measured MAF reading to the modeled MAF and has detected a series of pulsations in the induction system that exceed a calibrated threshold. A snapshot of Induction Data will show the fault, however, it may be necessary to compare the snapshot data to another vehicle to note a fluctuation and/or a difference in the desired vs. requested boost level.

When diagnosing DTC P2261, follow Circuit/System Testing step #1 closely. This step calls for inspecting for any vacuum leaks, damage, restrictions, improper routing or connection of the vacuum hoses on the charge air bypass valve solenoid, the charge air bypass valve, and the charge air bypass valve vacuum tank.

A leaking vacuum tank will cause DTC P2261. When testing the vacuum tank, care must be used or the results may not be valid.

The vacuum tank has an integral check valve not noted in SI. To check the vacuum tank operation, disconnect the hose that runs from the tank to the bypass valve solenoid at the solenoid and apply vacuum to the tank. The tank should be able to maintain vacuum with no decay. If the vacuum hose is removed from the intake manifold and plugged and the decay stops, the check valve is leaking. If the decay continues, the tank itself is leaking.

TIP: Front wheel drive platforms using the 2.0L engine (RPO LNF) incorporate a charge air bypass valve supplemental vacuum tank. The purpose of the tank is to provide an instant source of vacuum to the bypass valve via the bypass solenoid (when it is commanded open by the ECM). This results in less pressure buildup under closed throttle conditions, thereby reducing compressor noise, surge and spool time.

- Thanks to Jeff Gorenflo

In rare instances on 2010 Equinox and Terrain models with the 2.4L engine (RPO LAF) built before August 17, 2009, DTC P0172, Fuel Trim System Rich Bank 1, may set along with a high long-term fuel trim (-19% or higher). There may not be any other concerns with the vehicle and the condition may be difficult to duplicate.

If SI diagnostics does not lead to a resolution, check the following:

1.     Remove the hose from the air box to the engine inlet. Inspect for flashing on the bottom edge of the air box outlet tube past the MAF sensor. It may help to use a flashlight. (Fig. 13)

If flashing is present, remove it with sandpaper or a file. Use care to remove only the flashing.

2.     Make sure the complete air filter housing is correctly assembled. Verify that the dirty side air cleaner resonator (the part in the fender), is fully seated in the air cleaner box. If the resonator is not fully seated, reposition the air cleaner box and/or the resonator for better alignment.

After service, reset fuel trims and test drive the vehicle while monitoring to verify the change/repair.

- Thanks to Jeff Gorenflo

(Fig. 14)

The 2009-2010 Silverado 2-Mode Hybrid and Sierra 2-Mode Hybrid offer an available soft tonneau cover (RPO VPB). A rattle or knocking noise may be noticed coming from the rear of the cab while driving with the soft tonneau cover in the closed position.

The noise may be the result of improperly stowed plastic buckles on the tonneau cover contacting the cargo box or cab.

Ensure that the buckles at the front of the cargo box are properly secured using the provided elastic cords.

- Thanks to James Will

On the 2007-09 Cobalt, HHR, Malibu, G5, G6, VUE; 2007 Ion; and 2007-08 Aura - with the 4T45 automatic transmission (RPO MN5 or ME7), the transmission may shift softly or erratically. These conditions may appear intermittently or set a DTC P1811.

During diagnosis, a low or high line pressure (actual versus desired) may be observed. This may be due to sediment or debris inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind and affect line pressure output.

Perform the Line Pressure Check as described in the appropriate Service Information. If the actual versus desired pressures are not within the values specified, inspect the PC solenoid valve for sludge or debris buildup. Replace the PC solenoid valve and, if necessary, clean the valve body. Install two magnets (part number 29535617) in the oil pan, per service bulletin #08-07-30-040B.

- Thanks to Ronald Mitchell

Technicians may experience some difficulty installing the new style ignition lock cylinder on the following models: 2008-2009 CTS (built prior to VIN breakpoint 90163371), 2005-2009 Cobalt (built prior to April 14, 2009), 2006-2009 HHR and Solstice (built prior to April 14, 2009), 2007-2009 Equinox (built prior to July 2008), 2005-2006 Pursuit (Canada only), 2007-2009 G5 (built prior to April 14, 2009) and Torrent (built prior to July 2008), 2006-2009 SKY (built prior to April 24, 2009) -- with an automatic transmission only.

Before installing the new lock cylinder, inspect the housing for debris or damage from the old lock cylinder. No tools are required for installing the new lock cylinder. When installing the lock cylinder into the housing, it must be fully seated to ensure it latches into position.

The old style lock cylinder is still used on models with a manual transmission. Do NOT use the old style lock cylinder on a vehicle with an automatic transmission. The original binding condition may return.

- Thanks to Jim Loomis

Imagine a vehicle with a no start condition and a dead battery. Measuring the amperage of a control module using a Fluke DMM (digital multimeter) in AC mode shows a reading of only 25 ma, but in DC mode, a reading of 335 ma reveals the continuous draw that would drain the battery. This type of scenario shows the importance of checking the multimeter's default settings before testing.

Versions 1-4 of the Fluke 87 multimeter defaults to reading DC amperage when set on the amperage or milliamp scale. The new Fluke 87-5 meter (version 5), when set on the amperage or milliamp scale, will default to reading AC current. (Fig. 15)

If a diagnostic test step is requesting a DC amperage reading to be taken and the meter is set on the AC amperage setting, the meter will display 0 amperage (or close to 0 amperage). This will cause an inaccurate test result that can cause the test to pass or fail when it shouldn't.

To avoid an incorrect test result when testing amperage, always check the multimeter's display to make sure it is either on the AC or DC setting. Use the unmarked blue or yellow button (depending on the version of multimeter being used) on the top left of the multimeter to select between the AC and DC readings.

- Thanks to David N. Nowak

This information applies to 2010 Enclave, Acadia and Traverse models built after the week of August 17, 2009.

When the inspection/fill plug is removed from the Rear Drive Module (RDM), a significant quantity of fluid may drain out of the differential housing. Some RDMs were filled with an additional 200ml of gear oil from the factory. This does not adversely affect performance or normal operation of the RDM. Additionally, if the inspection/fill plug is removed, it is not necessary to over-fill the RDM beyond the approximate fluid capacity of 0.8 liters (0.85 quarts) for these vehicles. Refer to the appropriate Service Information for Rear Axle Lubricant Level Inspection.

- Thanks to Jonathan Johnson

The roof rail moldings, RPO V2P, on the 2010 Traverse built after August 16, 2009, have changed internally, but look the same from the exterior. The structural C-channel for mounting the VQQ "LPO Black Roof Rack Cross Rails" has been removed.

On vehicles built after August 16, 2009, it is necessary to install the C-channel to be able to install the optional cross rails. Option VQQ is no longer available and has been replaced with option S49 "LPO Luggage Rack Longitudinal C-Channels and Cross Rails" on LT and LTZ models.

Do not replace the roof rail moldings for missing C-channels on these vehicles.

- Thanks to Jeremy Richardson

The radio/HVAC display on the 2008-2009 G8 with the 6-disc CD changer audio system (RPO UWP) (Fig. 16) may intermittently go blank, but the radio and climate controls continue to operate. Some customers may comment that cycling the key eliminates the blank display.

Through warranty parts returns, the cause of the blank display condition has been found to reside in the radio and not the radio/HVAC display.

The radio is located in the passenger compartment, in the center of the instrument panel, behind the radio/HVAC display.

Do not confuse the blank radio/HVAC display with the normal dimming of the radio/HVAC display due to the automatic headlights coming on. When the auto headlights illuminate, the intensity of the display will be reduced to the requested backlighting setting.

If the radio/HVAC display is blank, replace the radio. Do NOT replace the radio/HVAC display.

TIP: Service information also refers to the radio/HVAC display as a radio/HVAC control.

- Thanks to David Eplin

An ENGINE POWER IS REDUCED message, an illuminated Check Engine lamp and DTC P0641 may be set on some 2006-2010 Impala and 2006-2007 Monte Carlo models. These conditions may be intermittent. Other DTCs that may set include: P0532, P0522, P0452, P0335, P0106, P0101 and P0068.

There are three areas where wire chaffing may occur and cause reduced engine power.

·       Inspect where the wiring harness is routed past the power steering pump. Verify that the harness is not rubbing on the power steering pump pulley.

·       Inspect the wiring harness where it runs over the transmission, under the air filter housing.

·       Inspect the wiring harness under the rear seat on the right side. If the harness is routed improperly, it may get pinched under the rear seat.

If any wire chaffing is found, repair the wiring per Service Information wiring repair procedures. Make sure the wiring harness is secure and properly routed to eliminate the chaffing condition.

- Thanks to David Eplin

A water leak, resulting wet carpet on the left front floor, may be found on some 2010 Equinox models. The leak may be caused by a gap or void in the seam sealer, in the cowl area on the left side of the vehicle.

Water may be entering the inside of the vehicle from a small hole just forward of the park brake pedal assembly. (Fig. 17)

Use a garden hose and water test the vehicle in the area of the left cowl, near the left hood hinge. Check for a leak on the inside of the vehicle. If a water leak is found, it will be necessary to seal this area. Follow the Body Waterleak Repair instructions in the Service Information.

- Thanks to Ange Girolamo

10209.11D -- Emerging Issues

November 12, 2009