For the past two years, dealers have been encouraged to support the Multiple PC Initiative (MPI), which calls for having one PC for each two technicians. A special thanks to all the dealers who have made the necessary investment; the results are very impressive.

Because dealers have taken that important first step, Service Operations can now take the next step -- to provide low-cost programming capability at each of those PCs. An added bonus is that diagnostics will soon be available at each PC as well.

There has been speculation for years about the “Tech 2 replacement.” Plain and simple, the Tech 2 is not being replaced in the near future, but there is a new piece of equipment coming out to work alongside the Tech 2. The new equipment takes advantage of all those new PCs installed in the service bays under the Multiple PC Initiative, and it is important news.

The GM Multiple Diagnostic Interface (MDI) EL-47955 is being shipped to NAO dealers during the second quarter of 2007, one per dealer (fig. 1).

TIP: Additional tools can be ordered by calling 1.800.GMTools, using prompts 1 or 4.

What is the GM MDI?

The GM MDI is a compact communication module that manages the transfer of data between a vehicle’s onboard ECU network and a PC.

The EL-47955 MDI is a kit of components (fig. 2):

A   GM MDI

B   J1962 Diagnostic connector

C   USB cable

D   Ethernet cable

E   AC adapter/power supply

      Wireless interface

      AAA batteries

      Owner manual

Operating software for the MDI will be downloaded from the TS2WEB website.

The GM MDI allows the user to perform Pass-Thru programming procedures using software running on a laptop or desktop PC.

TIP: Any PC can be used, so long as it meets the PC Hardware Specification located at this link:
http://www.gmde.net/standards.cfm
(in Canada, review GM Dealer Infrastructure Standards located on the GM infoNET).

Benefits of the GM MDI

Today, the dealer cost to equip a technician to diagnose and reprogram vehicles is $2880 USD (Tech 2 and CANdi). When software coverage on the GM MDI is fully operational, all diagnostic and reprogramming for GM vehicles globally will be supported with this one piece of hardware at a dealer cost of less than $800.00 USD.

The GM MDI offers faster programming speed at a lower cost. Depending on vehicle architecture (protocols/modules), the GM MDI can be 20-70% faster than the Tech 2. This helps alleviate vehicle battery drain problems during programming.

Using the GM MDI for programming also frees up your Tech 2 for diagnostics and other tasks.

No additional PCs are needed. PCs that have been installed under the Multiple PC Initiative (MPI) meet the PC Hardware Specification when using the GM MDI.

What Protocols does the GM MDI Support?

For immediate use -- At present, vehicles have two buses on the 16 pin connector (high speed and low speed GMLAN). The GM MDI communicates using all of the existing GM protocols, the same as the Tech 2:

- UART

- Class 2

- KWP2000

- GMLAN (CAN)

For future use -- Global architecture coming in July 2008 for MY 2009 will use a total of 4 GMLAN links. (This is a limited rollout in MY 2009.) Global architecture adds a medium speed bus and an expansion bus. The Tech 2 and CANdi module can run only low and high speed, and won’t work on the 4 GMLAN link system for diagnostics or programming. The MDI will have this capability.

How is the GM MDI Connected?

The GM MDI will be connected between the vehicle and the PC using the DLC and cable.

Connection between the GM MDI and the PC can be accomplished several ways.

- using the supplied cable to connect the mini USB port on the GM MDI and the USB port on the PC

- using a standard CAT5 cable to connect the Ethernet port on the GM MDI and the Ethernet port on the PC

- using the WLAN card built into the GM MDI to communicate with the PC through the dealership’s wireless network

MDI connections -- bottom (fig. 3)

A  Trigger switch connector

B  Vehicle Interface connector

C  Power connector (AC adapter)

MDI connections -- top (fig. 4)

A  Mini USB connector

B  Ethernet connector

The GM MDI is powered through the DLC when connected to the vehicle. In addition, it has 4 AAA batteries for backup. The unit can also be powered using the provided AC adapter plugged into any 120V AC electrical outlet.

Detachable port covers protect these connectors:

- Mini USB

- Ethernet

- Trigger switch

- Power

What are the Features, Controls and Indicators of the GM MDI?

The GM MDI has an easy to grip, comfortable, rugged enclosure. Rubber end covers offer extra shock resistance.

MDI controls (fig. 5)

A  On/off switch

B  Status LEDs

C  Vehicle Interface cable

A row of LEDs is located adjacent to the on/off power button to provide information about status and operation.

How Will the GM MDI be Used?

The GM MDI is initially being introduced with Pass-Thru programming capabilities only. It can be used to perform Pass-Thru programming on all vehicles built since 1993 and will support all vehicles into the future.

The GM MDI will be required to perform diagnostics on selected NAO vehicles for model year 2009. Diagnostic software is scheduled to be released for the GM MDI during the fourth quarter of 2008.

When diagnostics are introduced, the MDI will also get a remote data record capability. This permits recording data during a road test, similar to the Tech 2 Snap Shot function. A trigger switch connector is provided for this purpose.

Regulations require programming procedures to be compliant with SAE Recommended Practice J2534. The GM SPS is compliant with SAE Recommended Practice J2534, and the GM MDI is compliant with the portions of SAE J2534 that are applicable for GM vehicles.

The Future of the Tech 2

The Tech 2 remains an essential tool through at least the 2010 model year. The GM MDI will not support past models when its diagnostic capabilities are introduced. And, the Tech 2 will continue to be needed to diagnose all vehicles from previous model years.

Remote programming with the Tech 2 will continue to be supported for use on all 2007 and previous vehicles.

Additional information will be supplied in future TechLink articles and dealer communications.

- Thanks to Mark Stesney

This information applies to:

- 2006-07 Cadillac DTS, Chevrolet Impala and Monte Carlo

- 2007 full-size utilities and pickups, Cadillac SRX, Pontiac Torrent, Chevrolet Equinox and Buick Lucerne

Technicians have encountered difficulty after replacing or SPS-programming a Remote Control Door Lock Receiver (RCDLR) when programming the Tire Pressure Monitoring (TPM) sensors.

The following three procedures must be performed in order, after replacing or SPS-programming an RCDLR.

1. Program Key Fobs

2. Set-up Tire Type/Pressure

3. Learn Tire Pressure Sensors

IMPORTANT: Step 2 (Set-up Tire Type/Pressure) must be done before attempting step 3 (Learn Tire Pressure Sensors).

If step 2 is not performed, it is not possible to successfully learn the tire pressure sensors. The Driver Information Center will continue to indicate that the TPM needs to be calibrated.

Refer to document 1684976 for detailed information on how to set-up tire type/pressure.

- Thanks to Gary Clark and Gary Hazen

On the 2006-07 DTS and Lucerne, the evaporator temperature sensor is part of the heater and A/C control lamp wiring harness (fig. 6) and must be serviced as an assembly.

A  Harness

This sensor is used with both manual and automatic control HVAC.

Pinch the evaporator temperature sensor locator tabs together from the inside of the HVAC case for sensor removal.

TIP: You can't pry the sensor out without breaking the case.

- Thanks to Jerry Garfield

When your dealership installs a new or remanufactured OnStar module, the unit removed from the vehicle is the “core,” and typically it must be returned to Autocraft Electronics. The core is considered “outstanding” unless it has been received by Autocraft.

OnStar and Autocraft Electronics have been working to reduce the cost and processing requirements for OnStar core returns. The result is a new “Virtual Core” return process. This process allows the dealer parts department to submit credit for a core by logging into the Autocraft Electronics website.

In most cases, after the Virtual Core process is completed, you will be able to dispose of the core instead of having to mail it in for credit. See below for exceptions.

TIP: See below for instructions for setting up an account.

Go to the Autocraft Electronics website at www.autocraft.com.

You can then easily access your dealership’s list of outstanding cores, by selecting Account Maintenance and then Outstanding Core.

This opens a list of the cores your dealership has outstanding and not yet returned. Select the Virtual Core button (fig. 7) to the right of a listed core to display the Entry Screen. Here you will enter the necessary information to perform the Virtual Core return, including STID, ESN and Part Number. These numbers are found on the label on the module.

TIP: If you make a mistake with the STID or ESN, you will see a message that tells you to try again. If the information you input does not match the record for the vehicle’s VIN, a message will tell you that the virtual core information cannot be verified.

If all the data matches, you will see a message that verifies virtual core information, and an authorization number appears. You can now dispose of the core.

TIP: In some cases, OnStar may want the unit back for assesment or remanufacture. Then, you will be instructed to mail the core instead of disposing of it.

- Thanks to Bob Casper

A 2006 Chevrolet Silverado or GMC Sierra equipped with the 6.6 LLY or LBZ diesel engine may have the SES light on, with DTC P0540.

A loose connection at the Intake Air Heater (IAH) fuse may induce a P0540. Complete the SI diagnostic for any trouble code or symptom found.

During diagnosis for the P0540, inspect for a loose connection at the IAH 175-amp Mega-fuse, located in the Underhood Bussed Electrical Center.

TIP: The left fender upper brace and the secondary UBEC cover need to be removed to inspect the IAH fuse.

Clean and tighten the connection at the 175-amp fuse and evaluate repairs.

- Thanks to Don Langer

The owner of a Saab vehicle may comment that the heated driver or passenger seat is inoperative at times.

TIP: Seat heaters on these cars have automatic thermostatic shut off in addition to switch controls. Resistances can change with age and these specifications may vary accordingly.

On 1979-93 900 models (and 1994 convertible), seat heating is disabled if the temperature of the seat is above 82° F (28° C). If no switch is present in the fascia, the seats are fully automatic and cannot be switched off.

On 1985-98 9000 models, seat heating is disabled if the temperature of the seat is above 82° F (28° C). The driver and passenger heated seats may be fully automatic or switched. Look for switches in the fascia.

On 1994-2002 900 and 9-3 models (and 2003 convertible), the temperature of the seat must be below 79°F (26°C) for seat heating to begin. Seat heating will shut off if the seat temperature rises above 97°F (36°C). Look for switches in the center console.

- Thanks to Jeff Gorenflo

The 2006 end year Vehicle Data Recorder (VDR) software J-42598-150 is available in early January 2007 (fig. 8). It adds model year 2007 powertrain coverage for GM vehicles. This software will support both the original VDR J-42598 and the new CAN+ VDR J-42598-B. GMLAN vehicles and live data screen will require VDR CAN+ hardware J-42598-B. This software is compatible with generic PC hardware and will operate on Windows 2000 Professional, and XP Professional.

OBDII Generic Support

An enhancement provided by the new software is the addition of OBDII generic support. This enables the VDR to be used with any OBDII compliant vehicle, not just GM vehicles. You will be able to record snapshots and view the OBDII data stream in the same manner as you can with the current GM data stream.

To use the OBDII option, click on the yellow Select Vehicle button on the left side top tool bar of the VDR Host Software. You must program the VDR in the same manner as you do when selecting a specific GM vehicle. See the user manual for additional instructions.

Software CD and Manual

The user manual for the CAN+ Vehicle Data Recorder J-42598-B is on the VDR Update Software J-42598-150 CD. Adobe Reader is required to view and print the manual. This is included on the VDR Update Software J-42598-150 CD.

To access the manual:

1. Install the VDR Update Software J-42598-150 CD on the PC.

2. If Adobe Reader is installed on the PC, go to step 4. Otherwise, click on START, PROGRAMS, GM VDR HOST APPLICATION, & VDR HOST MANUAL READ ME.

3. Follow the installation instructions on the pop up screen.

4. Click on START, PROGRAMS, GM VDR HOST APPLICATION & VDR HOST MANUAL.

Review of Past Enhancements to the GM VDR.

The live PC data screen allows you to view live data stream information on a standard desktop PC or laptop. To use the Live Data screen, connect the VDR DLC cable to the vehicle and the serial cable (same as Tech 2 serial cable) to a computer running the VDR Host Software.

Select a vehicle, then click on the Live Data button on the top right of tool bar on the VDR Host Software. The same screen that displays the snapshot data will display the live data stream information. DTCs can also be displayed and cleared while viewing the live data stream. See the user manual for additional instructions.

The standard Save As option makes it more convenient for you to save a snapshot to the PC’s hard drive or a removable drive such as compact flash or USB flash drive.

TIP: The VDR is useful in solving intermittent driveablility problems, but also has additional uses such as viewing live data (explained above), and capturing information during the crank mode. The CAN+ VDR can be set up to capture data while cranking. This could be helpful in diagnosing a crank/no start or cold/hot start condition.

- Thanks to Mike Banar

This information applies to all 1990-93 Saab 900 and 1994 Saab 900 Convertible.

A vehicle may experience a repeat DTC 30/S setting as an external fault in the SRS. It may not be possible to duplicate or the code may reset immediately. The code may be listed as 41-03-XX-XX-30-S.

The technician may follow the diagnostic procedure in manual 8:6 Airbag and find no faults. The code may be listed as 41-03-99-99-30-S. This code may set by an intermittent contact in the ignition switch. Replace the ignition switch, clear codes and retest.

Code Breakdown

The first series of numbers is the SRS code system designator. 41

The second series of numbers are the program versions. 03 or 04

The third series of numbers are the hours the fault is present. Up to 99

The fourth series of numbers are the minutes the fault is present. Up to 99

The fifth series of numbers are the code identifiers. (multiple codes)

The sixth and last series of numbers are the fault types
S = short term
L = long term

This is a copy of diagnostic procedure Remedy 14 from 8:6 Airbag:

- A short circuit to ground may be indicated by the SRS lamp remaining on continuously when the ignition is switched on.

- A short circuit to battery positive may be indicated by the SRS lamp not lighting up at all for the first six seconds after the ignition is switched on. The continuous fault duration must be at least 20 seconds before the fault code is stored in memory.

Diagnosis: Check cable 920A from pin 20 of electronic unit through pin 7 in connector H10-2 and on pin 6 of combined instrument. Also check cable 920 between pin 7 in connector H10-2 and pin 10 of test socket H10-3 for a short circuit to ground or battery positive terminal.

- Thanks to Jeff Gorenflo

This information applies to 1997-2005 GM cars, light duty trucks and utilities equipped with 4L60E, 4L65E or 4L70E (RPO M30, M32 or M70) transmissions.

A replacement pump cover may appear different from the original pump cover. The replacement pump casting may have a boss or a hole and plug to accommodate an input speed sensor (ISS).

Using a light, look inside the stator support and inspect the stator support shaft sleeve. If the sleeve has a large hole and notch, it cannot be used in 1997-2005 transmissions (fig. 9). If the sleeve does not have the large hole and notch in the sleeve it can be used in 1997-2005 transmissions.

A  Notch and hole for ISS equipped pump cover -- CANNOT be used in 1997-2005 transmissions

B  Non ISS equipped -- CAN be used in 1997-2005 transmissions

- Thanks to Chuck Krepp

On a 2007 Buick Terraza, Chevrolet Uplander, Pontiac Montana SV6 or Saturn Relay built before July 24, 2006, the A/C may blow warm or is inoperative.

This is the result of a leak in the low pressure A/C line, which is attached to the compressor closest to the A/C pulley/clutch assembly. The leak is due to the positive battery cable from the starter being routed under the A/C line, applying upward pressure on the A/C line. Over time, this may result in a fractured line or a leak.
Replace the low pressure line and reroute the positive battery cable over the A/C line
(fig. 10).

- Thanks to Ron Erman

Some 2006 Cadillac DTS owners may comment that in the heater mode, the airflow to the driver footwell area is low, or warm air cannot be felt at all. They may also mention that the blower needs to be on high and the temperature set high to maintain comfort.

This condition may be caused by the floor duct (which is part of the I/P closeout/insulator panel) being mis-aligned with the left heater duct. To correct, replace the left I/P closeout/insulator panel (p/n 10368444).

For further information, refer to Bulletin 06-01-37-005.

- Thanks to Bill Denton

On some 2006-07 Buick Rendezvous with 3.5L (LX9) engine, the fuel gauge fluctuates or operates erratically.

Update the Powertrain Control Module (PCM) using the latest calibration available, then retest. Be sure to read the descriptions of available calibrations and choose the p/n that specifically addresses an erratic fuel gauge issue and matches the correct EGR type.

TIP: This new calibration will address fuel gauge fluctuation concerns for customers who typically park their vehicle on an incline.

- Thanks to Charles Avritt

On some 2007 Saturn IONs, it may be difficult to turn the ignition key to the Run position.
A tab may be improperly placed in the ignition housing (fig. 11). Pivot lever (A) interferes with camshaft (B) at corner. This will require replacement of the housing on cars from VIN 7S825114 to 7S834111. It cannot be repaired. The part number for the replacement housing is 10392736.

- Thanks to Jeff Gorenflo

On a 1999-2005 Saab 9-5 sedan the cruise control may be inoperative with no diagnostic trouble codes stored. The Tech 2 usually indicates all cruise control switches are working correctly, but the Gear Detected parameter always shows OFF.

Check the rear lamp harness near the left trunk hinge for chafed or broken wires. If the reverse light circuit goes open, DICE will interpret that as the reverse light switch being closed, and the Tech 2 will show OFF for Gear Detected.

- Thanks to Jeff Gorenflo

At first glance, it may appear that the new 2007 Silverado and Sierra fullsize pickups, full-size utilities, Cadillac DTS and Buick Lucerne do not have a Tire Pressure Monitor (TPM) system. All of these vehicles with TPM have a black rubber valve stem instead of the previous metal stem.

To recognize a rubber valve stem with TPM, look for these clues (fig. 12):

- Valve stem cap (A) is longer than usual

- There is a larger than normal amount of exposed brass (B) when the valve stem cap is removed

- The valve stem feels thicker and heavier (C) than most rubber valve stems

The valve stem can be detached from the TPM sensor electronic housing by removing the attaching screw (D).

TIP: Replace the valve stem with a new valve stem at each service event.

The TPM sensor can be retained with the vehicle and attached to the new valve stem. The service part kit to replace the valve stem, including a new screw, is p/n 15263240 for all applications.

Torque the retaining screw to 1.3 N-m (11.5 lb-in).

TIP: The spare tire does not have a TPM sensor.

- Thanks to Jim Will

On a 2007 Saab 9-5 with OnStar Gen 7.0X hardware, the OnStar red LED may be intermittent. A DTC B2476 may be current or in history. The button assembly or VCIM may have been replaced with no change.

The Saab button assembly draws less current than the LEDs used in other GM vehicles. The system is working normally, but may set a B2476 and illuminate the red LED.

Download the Tech 2 update as explained in the box below. (Saab dealers in Canada need to contact OnStar TAC.)

TIP: This is specific Tech 2 software for this DTC. After updating the vehicle with this software, it is necessary to reload the latest version of Tech 2 software (126.000) from TIS. To avoid multiple Tech 2 program changes, it is recommended that all cars in dealer inventory be updated at the same time.

Connect the Tech 2 to the vehicle and make to following selections:

- Diagnosis / 2007 / 9-5 / Body / OnStar / Spare part programming

- For corporate radio select EHU

- For Navigation radio select IHU

- Exit and disconnect Tech 2

Return the vehicle to the customer

No security access is required for this programming.

TIP: All 2007 model 9-5s below VIN 73507800 should be checked for this DTC during PDI.

- Thanks to Jeff Gorenflo