With the introduction of the LH8 small-block V8 engine in the 2008 Hummer H3 Alpha, GM is implementing a new design accessory drive belt (fig.1). It's called a "stretchy" belt, and it doesn't have a belt tensioner. In one respect, the stretchy belt resembles a rubber band -- it applies tension when it's pulled slightly beyond its relaxed length.

The once-universal V-belt had two drawbacks. First, one of the accessory drive components had to be adjustable in order to install and apply tension to the belt. And second, as the belt was used, it became necessary to check and occasionally adjust tension.

The serpentine belt eliminated both of these drawbacks by adding a spring-loaded tensioner that eased installation and automatically maintained the proper tension. But the tensioner added cost, weight and complexity.

The stretchy belt goes even further. Its big advantages are that it doesn't require a tensioner, simplifies design and eliminates weight from the engine.

Initially, the stretchy belt is being used between the engine balancer and AC compressor. It eliminates the need for a secondary belt tensioner. The serpentine belt continues to be used to drive the power steering pump, generator and water pump and remains unchanged. The primary belt is tensioned by the primary belt tensioner.

Just What is a Stretchy Belt?

The outward appearance of the stretchy belt is similar to the current design serpentine belt. The new design reinforcing cord (fig. 2) provides its unique qualities. The new belt cord is made of a polyamid material. The polyamid cord is more elastic thant the more traditional aramid or plyester cord designs.

A   Back compound

B   Reinforcing cord

C   Cushion compound

D   Rib compound

Polyamid cord, when combined with a more elastic backing compound, ensures that the belt is able to maintain the specified tension within the specified range of usage. The belt is designed to maintain tension for 150,000 miles (240,000 kilometers).

How is the Stretchy Belt Serviced?

IMPORTANT: The stretchy belt must not be re-used. Always replace with a new belt.

Removal -- To remove the stretchy belt, simply cut it with a razor knife or cutting pliers
(fig. 3)

Installation -- As implied by its name, the stretchy belt is installed by carefully stretching it over the flanges of the pulleys. Nothing has to be loosened, and there is no tensioner.

TIP: The replacement stretchy belt is packaged with a disposable installation tool.

1. Position the belt behind the rear face of the balancer and off of the AC pulley. Install the tool onto the balancer (fig. 4).

A   Installation tool

2. Slide the tool upward, installing the belt onto the tool (fig. 5). Slide the tool downward, positioning the belt onto the AC pulley and applying light tension to the belt.

A   Installation tool

B   Belt

3. Position the lower portion of the belt with the ribbed area facing forward (fig. 6).

4. Using a breaker bar and socket on the balancer bolt, rotate the crankshaft balancer slowly in the clockwise direction (fig. 7). At the same time, using a second hand, ensure the belt ribbed area remains facing forward. Use mild finger pressure to pull the belt forward to ensure the belt aligns properly to the AC pulley.

5. Inspect the belt for proper alignment onto the AC pulley (fig. 8).

6. With the belt located on the pulleys, rotate the balancer an additional 360° to ensure proper belt installation (fig. 9).

- Thanks to Ron Minoletti

Refrigerant recovery recharge equipment such as your ACR2000 is built to conform to standards set by the Society of Automotive Engineers (SAE). Occasionally, it becomes necessary for the SAE to replace old standards with new ones as conditions change. Such a change becomes effective in December 2007. Here are some details.

SAE J2788 replaces SAE J2210 as the new standard covering all mobile refrigerant recovery recharge equipment. SAE J2788 contains several mandates that enhance vehicle AC service for two key reasons.

- The standard reduces the amount of refrigerant that can be lost to the atmosphere, due to growing concerns over global warming and greenhouse gas emissions.

- The standard also more tightly controls the equipment accuracy for recharging, due to OEM vehicle system refrigerant capacities becoming smaller, which requires a more accurate charge for peak operating performance.

What Happens When the New Standard Goes Into Effect?

- After December 2007, equipment manufacturers will no longer be able to produce equipment that meets the old J2210 standard.

- The EPA (Environmental Protection Agency) is in the process of rewriting the Federal Registry which will likely prohibit sale of SAE J2210 equipment at the end of March 2008.

- The EPA does not plan to ban the use of J2210 equipment. Current J2210 equipment can continue to be used by service locations for the useful life of the equipment.

- Purchase of new compliant equipment is not a requirement of SAE J2788 or the EPA.

To summarize, you can continue to use your ACR2000 as long as it functions properly. When a replacement is needed, the replacement must conform to the new SAE standards. New equipment is under development, and should be available sometime in 2008.

Comparison Between New Standards and ACR2000 Specifications and Standards

This information is provided to give you an idea of the differences between the old and new standards.

- Thanks to Brian Echtinaw

An updated version of the GM6094M Approved Engine Oils list is available in the Reference Guide section of the TechLink website. GM has recently conducted a test program to check several of the oils on the Approved Oils list for compliance with the GM6094M specification. One of the oils tested during this program, Castrol GTX, was found not to meet the GM6094M specification, and so this oil has been removed from the Approved Oils list.

Watch for further updates to the GM6094M and GM4718M Approved Products list on the GM Techlink website.

- Thanks to Matt Snider

This information applies to the 2007 full-size utilities from Chevrolet, GMC and Cadillac with reading lamps or overhead consoles with map/reading lights.

It is no longer necessary to replace the entire lamp if the switch becomes inoperable.

Simply remove the lens and remove the pushbutton from the switch (fig. 10). Then use a suitable tool to pry the switch from the electrical contacts and remove the switch through the keyhole slot (fig. 11).

The new service switch assembly p/n 25877453 replaces the current switch assembly.

- Thanks to Dave Roland and Mike Bates

On an Enclave, Acadia or Outlook, a clunk, thud or pop noise may be heard or felt in the left front area of the vehicle during the anti-lock brake system (ABS) initialization self test. This may be described as similar to driving over a manhole cover. The initialization test happens one time per ignition cycle.

The initialization test starts when the vehicle is driven at a speed greater than 12 km/h
(7.5 mph) and the EBCM has not detected any traction control module (TCS)/vehicle stability enhancement system (VSES) related malfunctions, and the brakes are not applied. The EBCM isolates all of the wheels by closing the four isolation valves. Because all of the wheels are isolated during the second phase of the test, the test must be aborted if the brake is applied while the test is being performed. Occasionally, the driver may detect this by experiencing a clunk, thud or pop noise or a momentary hard pedal.

These are normal characteristics of the anti-lock brake system (ABS) initialization self test, and no repairs should be made.

- Thanks to Ron Erman

On a 2007 full-size utility, it may be difficult to program the TCCM, or programming fails.

Be sure the battery is fully charged and all accessories are off, including the auto headlamps. Use the Pass-Thru method instead of remote programming.

If programming fails after a partial or full programming event, or an SPS error code is received, contact Techline at 800.828.6860 (English) or 800.503.3222 (French).

TIP: Use the Midtronics 165-PSC charger, or a 12-volt jumper pack to maintain battery charge during programming (June 2006 TechLink).

- Thanks to Charles Krepp

Visit www.i-car.com to find courses. Click on the GM logo on the home page to be directed to a GM-specific class search page.

While GM STC recommends the GM Dealer Windshield Direct Delivery Program, other available training (including hands-on installation training) are offered through the National Glass Association and Automotive Glass Consultants.

For more information:

I-CAR customer care -- 800.422.7872 or log on to www.i-car.com.

GM Training Help Desk -- 888.748.2687 or log on to www.gmtraining.com.

National Glass Association -- Contact Julie Pearce at 703.442.4890 ext. 134

Automotive Glass Consultants -- 800.695.-5418 or email bberanek@aol.com.

This information applies to installing a Bluetooth kit on 2001-07 Saab 9-5, 2003-07
Saab 9-3 Sedan, and 2004-07 Saab 9-3 CV (fig. 12).

TIP: While not listed on the instructions, these kits also fit 2004 and later convertibles.

This feature was designed around two separate kits.

- 32 025 907 Hands Free Kit

- 32 025 900 Adapter Harness, Mobile Phone

Depending on vehicle configuration, the car may require both kits.

Vehicles equipped with TEL1 do not need the adapter harness (32 025 900) installed. These vehicles can be identified by squeezing the "shark fin" antenna. If the antenna will not bend, there is an antenna inside the outer shell. These cars also have a microphone in the overhead console (although it will not be utilized for this kit). These vehicles have connector 375 factory installed and do not need the adapter harness. Connector 375 is located behind the EHU and can be difficult to locate.

All other vehicles require the adapter harness.

This hands-free kit is not compatible with OnStar, so it cannot be installed in vehicles with OnStar.

The installation instructions for the adapter harness list the 2007 9-3 with Navigation as an applicable variant. U.S. spec 9-3 models for the 2007 model year require OnStar when the Navigation system is chosen; so this kit cannot be installed on a 2007 9-3 with Navigation.

The installation instructions have been placed in the CCG for viewing, and they are also located in IRIS.

- Thanks to Jeff Gorenflo

Starting with MY 2005, GM introduced Tire Pressure Monitoring (TPM) Systems in select vehicles. The number of GM vehicle lines with TPM systems has increased each year since 2005. Beginning in October 2007, all GM vehicles will be equipped with Tire Pressure Monitoring, with the exception of vehicles over 10000 GVW or heavy duty "dually" pickups.

During normal diagnosis, repair, or maintenance of a GM vehicle, it may be necessary to determine if the vehicle is equipped with TPMS. For GM vehicles built before October 2007, there are several ways to recognize whether or not a vehicle is equipped with a TPMS.

Using a scan tool (Tech 2) -- select the Remote Control Door Lock Receiver (RCDLR) and Module ID Information. For vehicles with a TPM system, the sensor IDs will be displayed (i.e., 123456) as well as the sensor location. For vehicles without TPM, nothing will be displayed in this location.

Using special tool J-46079 -- go to any tire and activate the sensor. If the vehicle is equipped with TPM, the special tool will activate the sensor, which will begin to transmit an ID. The ID will display on the tool.

If these tools are not available, a visual inspection can determine if the vehicle has a TPM system. Refer to the following examples for the various valve stem types you may encounter (fig. 13):

1. Clamp-in type TPM sensor -- characterized by a metal non-replaceable valve stem secured by an attaching nut visible on the outside of the wheel.

2. Snap-in TPM sensor -- characterized by:

a. Black rubber valve stem

b. Valve stem cap longer than traditional non-TPM stem

c. Valve feels thicker than non-TPM valve

3. Non TPM -- heavy duty brass bodied valve stem.

4. Non TPM -- common standard duty valve stem.

- Thanks to Steve Falko

Some owners of a 2007 Silverado or Sierra pickup may comment on a poor appearance of the end caps used on Silverado/Sierra Accessories Tubular Bed Rails (p/n 19154652 and 19154653) where the end cap halves may not properly mate once installed.

To prevent this from occurring, the front and rear stake pocket bolts should be snug before installation of the end caps. If overtorqued, the inner and outer end caps will not properly close once the end cap fasteners are tightened. Once properly installed, a 3 mm gap should exist between the two end cap halves (fig. 14).

A   3 mm gap

- Thanks to Jim Will

The IntelliBeam™ Intelligent Headlamp System is an enhancement to the vehicle's headlamp system. Using a digital light sensor located on the rearview mirror, this system turns the high-beam headlamps on and off according to surrounding traffic conditions.

IntelliBeam is available on Cadillac DTS, STS and Escalade (fig. 15). An understanding of proper operation will help determine if diagnosis and service are needed.

TIP: If a customer misinterprets normal operation as a malfunction, it is necessary to help them understand that the system is operating as designed.

Turning On and Enabling IntelliBeam

IntelliBeam must be both turned on and enabled before it will function.

Turning On -- Press and release the IntelliBeam button on the inside rear view mirror. The IntelliBeam indicator on the mirror turns on. Once the system has been turned on, it remains on each time the vehicle is started. Additionally, the IntelliBeam system must be enabled.

Enabling -- Turn the exterior lamp control to AUTO, with the turn signal/multifunction lever in its neutral position. The High-Beam On light appears on the instrument panel cluster when the high-beams are on.

IntelliBeam Operation

High Beams -- With the IntelliBeam system turned on and enabled, the high-beam headlamps turn on when:

- it is dark enough

- there is no other traffic present

TIP: IntelliBeam activates the high-beams only when driving over 20 mph (32 km/h).

Low Beams -- The low-beam headlamps turn on under the control of IntelliBeam when any of the following situations occurs:

- The system detects an approaching vehicle's headlamps.

- The system detects the taillamps of a vehicle ahead.

- The outside light is bright enough that high-beam headlamps are not required.

- The high-beam headlamps are manually turned on or the flash-to-pass feature is used. When either of these conditions occurs, the IntelliBeam feature is temporarily disabled until the high-beam stalk is returned to the neutral position. If either of these conditions occurs and IntelliBeam already has the high-beam headlamps on, the IntelliBeam feature is disabled and the IntelliBeam light in the mirror turns off.

- The exterior lamp control is turned to any setting except AUTO. When this occurs, IntelliBeam is disabled until the control is turned back to the AUTO position and the AUTOMATIC LIGHTS ON message displays on the DIC.

- The IntelliBeam system is turned off at the inside rearview mirror.

- The vehicle's speed drops below 15 mph (24 km/h).

High Beams May Remain On -- IntelliBeam may not turn off the high-beams if the system cannot detect another vehicle's lamps because of any of the following:

- The other vehicle's lamps are missing, damaged, obstructed from view, or otherwise undetected.

- The other vehicle's lamps are covered with dirt, snow and/or road spray.

- The other vehicle's lamps cannot be detected due to dense exhaust, smoke, fog, snow, road spray, mist, or other airborne obstructions.

- Cadillac's windshield is dirty, cracked, or obstructed by something that blocks the view of the IntelliBeam light sensor.

- Cadillac's windshield is covered with ice, dirt, haze, or other obstructions.

- Cadillac is loaded such that the front end of the vehicle points upward, causing the IntelliBeam sensor to aim high and not detect headlamps and taillamps.

- Driving on winding or hilly roads.

- Thanks to Chris Graham

This information applies to 2005-06 Escalade, Avalanche, Suburban, Tahoe, Denali, Sierra, Denali, Yukon XL and 2005-07 Silverado and Sierra Classic with Regulated Voltage Control (RVC) module.

A vehicle may have an intermittent battery lamp with a history code B1489 in the Battery Generator Control Module (BGCM). This concern may be noticed after the BGCM has been replaced for another issue.

Whenever the BGCM is replaced, the module needs to be SPS programmed before the vehicle is released to the customer. If the calibration was not completed properly or the vehicle left the dealership with the module not programmed, a DTC B1489 code may be set, followed by a intermittent battery lamp.

TIP: If there is a programming issue with the module, please contact Techline Customer Support.

- Thanks to Paul Radzwilowicz

The OnStar upgrade, from analog to digital, is covered in detail in bulletin 05-08-46-006 and in the February 2007 issue of OnStar Service Professional (ONS-SRVPRO-0207) available from the DWD store. Refer to these documents for in-depth information on obtaining and installing the upgrade kit. Here are some reminders and tips.

Configuration Process

After replacing the Vehicle Communication Interface Module (VCIM), it is essential to configure the new OnStar system. Failure to configure the system will result in an additional customer visit for repair.

DO NOT press and hold the white dot button on the keypad. This will not reset this version of OnStar and may result in a DTC being set.

Use the TIS2WEB and SPS applications, along with your Tech 2, to perform the configuration and set-up procedures. This is now a two-step procedure which enables an automated activation by the OnStar Center, without a button press to the OnStar Call Center.

IMPORTANT: The VCIM has a set of numbers that match the module to a specific vehicle. These numbers, the 10-digit station identification (STID) and 11-digit electronic serial number (ESN), are used by OnStar and the cellular network to identify the vehicle. The VCIM MUST NOT be exchanged with a module from another vehicle.

The TIS2WEB submission must be performed only once. Multiple submissions will result in an unconfigured vehicle and in some cases a service comeback.

1. Connect the Tech 2 to the vehicle.

2. Connect the TIS terminal to the Tech 2.

3. Use the SPS to select TIS2WEB Pass-Thru OnStar Activation (Replaced/Upgraded Units Only).

4. On completion of the TIS2WEB step, disconnect the TIS terminal from the Tech 2 and perform the VCIM/OnStar Set-up procedure using the Tech 2. The set-up procedure is located under the special function menu option.

IMPORTANT: Failure to perform these steps will result in a red LED, a DTC to be set, and limited or incomplete OnStar services.

TIP: The default language of the VCIM is English. To change to Spanish or French, access the special function menu on the Tech 2 and follow instructions.

IMPORTANT: OnStar Emergency Services are available immediately after completion of these steps. Full configuration, including activation of Hands-Free Calling, may take up to 24 hours to complete.

Installing On-Glass Antenna

On some vehicles listed in the bulletin, the on-glass antenna mast and inner and outer couplers are replaced with components included in the kit. Follow instructions carefully to be sure the antenna is installed in the correct location and that it adheres properly.

TIP: When installing the antenna to the window glass, use Adhesive Promoter. This material is not included in the OnStar upgrade kit and is considered a shop supply. It must be obtained in a bulk container under p/n 12378555 (88901239 in Canada). Follow instructions on the container.

GPS Antenna Jumper Cable

On 2002 Cadillac DeVille and Seville models, the GPS antenna jumper cable is clipped to the back seat cross brace. The short length of jumper cable does not allow the VCIM mounting bracket to be pulled back very far before the connector breaks at the VCIM.
DO NOT pull back on the mounting bracket until the GPS antenna jumper cable is unclipped from the back seat cross brace or unplugged from the VCIM.

- Thanks to Frank Pompa

For the past several years, you've probably heard talk about GM's next generation of hybrid vehicles. The GM Service Technical College (GM STC) is releasing the first of several
Two-Mode Hybrid courses including WBT, IDL and Hands-On components

In June 2007, the following two courses are available and will be required for all service technicians, as a 2007 STS requirement in the Fundamental category. Dealers will have 3 months (90 days) from the date the courses are released to take them before it will have any affect on their STS percentage.

These courses will appear on the 2007 STS report as a STS requirement in the Fundamental category.

For additional information and answers to questions, contact the GM Training Help Desk at 888.748.2687 or visit online at www.gmtraining.com in the Contact Us area.

- Thanks to Hershel Burson