October 2008 Archives

Lane-change accidents are caused by blind spots created by vehicle architecture, mirror resolution and a driver's physical capability to accurately assess a vehicle's presence, closing rate of speed and distance. Drivers changing lanes unaware of adjacent vehicles are the source of many near collisions every day (fig. 1). They are also the source of numerous damaged vehicles and injured people in North America each year.

Introduced in the 2008 model year, Side Blind Zone Alert (SBZA) is an increasingly available option for a number of higher-end GM vehicles including the new 2009 full size trucks. Side Object Detection (SOD) is another term sometimes used for this feature.

By appropriately illuminating amber icons in the outside rear view mirrors, this supplementary system alerts drivers to the presence of other road users as they pass through the vehicle's left and right side blind spots (fig. 2). An icon will flash to heighten the alert when turn signals are active on that side of the vehicle (fig. 3).

IMPORTANT: SBZA is only a lane changing aid and does not replace driver vision. SBZA does not detect vehicles which may be rapidly approaching outside the side blind zones,
or pedestrians, bicyclists, or animals.

The system is relatively simple. Sensors are located behind the left and right rear fascia sides. They scan adjacent road lanes and control their corresponding mirror alert icons by GMLAN serial data communication to the door zone modules. In turn, the door zone modules switch power to the LED indicators within the mirrors.

SBZA can be turned on and off through a Driver Information Center (DIC) menu selection
or an option on the navigation screen. The DIC also alerts the driver to 'SBZA unavailable' and 'needs service' conditions.

The SBZA unavailable message occurs when sensor performance is degraded by the presence of water and is typically triggered by rain, snow, mud or ice. If the system does not self-recover once dry conditions have apparently returned, check that the sensors are clean and no labels are present on either side of the fascia.

As described in the owner manual, occasional false alerts on roadside infrastructures (such as guardrails, vegetation, etc.) or missed alerts are not service issues and are within normal operation.

TIP: Because a trailer can interfere with the system's operation and the detection zones do not alter when a trailer is attached, it's preferable to switch the system off when towing.

TIP: Always use the same part number when a replacement has to be made. Left and right sensors are identical and must always have the same part number. A harness ground connection automatically configures sensors for right hand side operation.

TIP: To avoid VIN mismatch lock-out problems, do not substitute parts from other vehicles.

Scan tools can be used to check DTCs on either sensor. History DTCs may indicate an intermittent condition and should be approached accordingly.

A DIC service SBZA message shortly after the mirror icons have completed their vehicle power-on bulb check generally indicates a current DTC. Door zone modules should be investigated if the bulb check fails.

TIP: Although often tied together in option packages, SBZA and Lane Departure Warning (LDW) are separate systems and should be treated as such. And as always, check for the latest service information and bulletins.

- Thanks to Simon Tong

Pay for VCI

Increasingly, vehicle buyers want to personalize or modify their vehicles. This can be accomplished several different ways, depending on what the owner wants to add.

One way is to purchase a kit from GM Accessories that changes the appearance or function of the vehicle. Examples include a roof rack, chrome wheel package or a two way remote start kit. Some of these kits are a straight bolt-on, and some need a software calibration changed to complete the installation.

Another alternative is to add a factory offered OEM option to the vehicle that it was not produced with. Often, these items are not offered by GM Accessories and need to be purchased as service parts. Examples include fog lights, an axle ratio change or a speed governor. Many times these items need the corresponding software to complete the installation.

Some of these reconfigurations are possible; others are not.

Over the past several months, the Techline Customer Support Center (TCSC) has received an increasing number of calls related to adding OEM factory options to a vehicle.

Before making a change to a vehicle, call TCSC at 1.800.828 6860 (English) or 1.800.503.3222 (French) to verify if your request can be supported. These types of modifications and support fall outside the normal support role of TCSC. To support these vehicle changes, Techline will bill the dealer's open account $50 USD per modification. This charge applies only to vehicles being reconfigured from their original build, and not part of a GM Accessories kit or normal programming support.

- Thanks to Matt Singer

An article in the September 2008 issue of TechLink explained that, beginning September 2, all warranty replacement navigation radios are on parts restriction through the Product Quality Center (PQC).

Bulletin 08-08-44-010B has been released with more detail about the parts restriction.
Here are some highlights.

TIP: Navigation radios with visible physical damage such as liquid spills or impact must be reviewed with the District Service Manager for appropriate coverage, before contacting the PQC. The dealership must note the DSM's approval on the R.O. along with the reason for the goodwill assistance. Refer to Bulletin 08-08-44-015 for more information.

With the parts restriction in place for warranty replacement navigation radios, you will be required to complete a part-number-specific questionnaire and then contact the PQC (do not call your Electronic Service Center as you will simply be referred to the PQC).

TIP: The information gained from these questionnaires is fundamental in helping GM identify and solve radio concerns as we strive to improve quality and increase customer satisfaction.

Reviewing the appropriate questionnaire will highlight published repair procedures to assist you in eliminating several known issues which could help prevent unnecessary navigation radio replacement. The PQC will capture information on the questionnaire and may direct you to published service information in the event you have not attempted the repair procedure. If a navigation radio is still required after proper diagnostics have been performed, the PQC will order the part for the dealer.

Bulletin 08-08-44-010B includes a table of all radio part numbers and the number of the corresponding questionnaire that must be completed for each radio. Copies of the questionnaires are included in the bulletin. Bulletins that pertain to specific radio issues are pointed out in the respective portions of the questionnaires.

TIP: Be sure to have completed these bulletin directives before contacting the PQC.

- Thanks to Terry Nicholas

Beginning with Tech 2 software version 28.007, the card copy function has been disabled. This function has been disabled due to the increasing issue of unauthorized software copying, primarily in the aftermarket. Software piracy is a growing concern for General Motors and its dealers as this behavior directly affects dealers' competitive advantage in
the marketplace.

Tech 2s should be updated on a regular basis using Tech 2 Software Download in TIS 2 Web. In the event Tech 2 software needs to be reinstalled (such as in a failed download), software can be reinstalled by selecting Custom from the Select Diagnostic Tool for Download screen, then the North American Tech 2 software folder you wish to download from the Applications For Downloading box in the Select the Applications screen.

- Thanks to Mike Waszczenko

There are two different Underhood Bussed Electrical Centers (UBEC) used in the Aveo -- 96539834 is used on the Hatchback model and 96539835 is used on the Notchback model.

The new Aveo Underhood Bussed Electrical Center (UBEC) uses a new ISO Micro Relay which uses both 4.8mm and 6.3mm terminals (fig. 4). The new relay looks like the common 280 relay you are used to seeing in most Bussed Electrical Centers.

A  280 relay

B  ISO Micro relay

There are two different ISO Micro relays used in the Aveo Hatchback UBEC. There is a high current (35 amp) black relay and gray relay for all circuits with less than 20 amp current flow (fig. 5).

A  Black relay (35 amp) 

B  Gray relay (less than 20 amp)

There are three different ISO relays used in the Aveo Notchback UBEC. There is a black high current (35 amp) relay and a gray relay for all circuits with less than 20 amp current flow, as well as the larger 13502674 Mini ISO relay (fig. 6).

TIP: In some cases the service relay part may have 5 terminals rather than the 4 terminal relay you may be replacing. In this case the fifth terminal has no function and the relay will work as a replacement part (fig. 7 and 8).

The service part number is 13502676 for the low current gray relays and 96484304 for the high current 35 Amp black relays.

REMOVING BEC COVER

To remove the BEC cover, press the large tab at the end and lift the cover off (fig. 9).

Continue to lift the cover up and away from the two rear tabs to completely remove the lid(fig. 10).

To remove the BEC from its mounting bracket in order to remove or gain access to the wiring harness connectors underneath the BEC, release the three tabs and lift the BEC
up (fig. 11).

- Thanks to John Roberts

General Motors uses two methods of naming cylinder banks in V engines.

For emission related components, cylinder banks are named using a Society of Automotive Engineers (SAE) recommended practice. Bank 1 is the cylinder bank that has number 1 cylinder, and bank 2 is the cylinder bank that does not have cylinder 1. Cylinder 1 location is given in service manual service category Engine Mechanical, within Engine Component Description.

For other than emission related components, cylinder banks are named Left and Right.
This is determined by looking toward the front of the engine from the flywheel end.
This method is used whether the engine is installed longitudinally or transversely.

- Thanks to Jerry Garfield

A 2007-08 Express, Kodiak, Silverado, Savana, Sierra or Topkick equipped with a 6.6 Duramax Diesel Engine RPO code LMM may experience an intermittent DTC P009E for fuel rail pressure relief valve performance setting.

Complete the current SI diagnostics for any symptoms or trouble codes set. P009E will set
if the ECM interprets a rapid loss of fuel rail pressure.

If the current SI diagnostics for P009E are inconclusive, there has been an updated calibration released to address intermittent P009E.

Reprogram the ECM with the latest calibration and evaluate the concern.

- Thanks to Donald Langer

This information applies to 2007-08 fullsize pickups and utilities with engine RPO L76, L92, LC9, LH6, LMG, LY2 or LY5.

Some customers may comment on a buzz and/or rattle noise that occurs at 40-45 mph
(64-72 km/h) and/or 1100-1300 rpm just before the V4 to V8 transition. The noise sounds
as though it's coming from within the IP. The cause may be the generator B+ cable misrouted on the outboard side of the engine oil level indicator tube (fig. 12). At 1200 rpm
in V4 mode (AFM), the engine oil level indicator goes into resonance and vibrates against the generator cable which produces a rattle noise in the vehicle.

A  Cable touching  oil level indicator tube

To correct this concern, reroute the generator B+ cable on the inboard side of the engine
oil level indicator (fig. 13). Be sure the generator cable has at least 15 mm of clearance to the engine oil level indicator tube.

B  15 mm clearance between cable and oil level indicator tube

- Thanks to Jim Will

This month (October 2008) a differential cooler assembly is available for the 2009 Cadillac CTS-V. The part number is 20792934 (fig. 14).

The system is designed to reduce the operating temperature of the rear differential fluid when the CTS-V is driven at extended high speed or in competitive driving. The CTS-V differential cooler includes a temperature switch to operate the system when high rear differential fluid temperatures are met. The rear differential housing has provisions for the temperature switch. Installation time is less than 2 hours.

The differential lubricant pump and cooler assembly are located under the vehicle and
are mounted to the rear storage compartment well (fig. 15). The cooler module assembly consists of a pump, a heat exchanger, an electric fan and assorted hoses/fittings.
All components except the external lines, temperature switch and fittings are located in
the Cooler Module.

Oil is pulled from the differential and pumped through a hose to the cooler/heat exchanger. The differential oil is cooled by dissipating heat as the 12 volt electric fan blows outside air over the heat exchanger. The cooled differential oil then returns to the differential.

TIP: The pump and electric fan can be turned on using the temperature switch bypass plug included with the kit.

If the vehicle is equipped with this system, rear differential fluid capacity is an additional 0.31 L (0.33 qt).

- Thanks to Jeff Miller

This information applies to the 2007-09 Acadia and Outlook and the 2008-09 Enclave.

IMPORTANT: Every time the shifter knob is serviced, the tip of the actuator rod and the top half of the exposed actuator rod toward the rear of the vehicle should be lubricated (fig. 16).

When replacing a shifter knob on these vehicles, the tip of the actuator rod and the backside of the exposed actuator rod need to be lubed with a special lubricant now available through GMSPO (fig. 17).