GM Service Manual Online
For 1990-2009 cars only

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Lack of communication may be due to a malfunction of the CAN serial data circuit. The specified procedure will determine the particular condition.

  2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

  3. The symptoms list in Symptoms will determine the correct diagnostic procedure to use.

  4. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Install a scan tool.

Does the scan tool power up?

Go to Step 2

Go to Scan Tool Does Not Power Up in Data Link Communications

2

  1. Turn the ignition ON, with the engine OFF.
  2. Attempt to establish communication with the following modules
  3. • Electronic Brake Control Module (EBCM)
    • Electric Power Steering (EPS)
    • Engine Control Module (ECM)

Does the scan tool communicate with all of the control modules?

Go to Step 3

Go to Scan Tool Does Not Communicate with Keyword Data Line in Data Link Communications

3

  1. Turn the ignition ON, with the engine OFF.
  2. Attempt to establish communication with the following modules
  3. • Body Control Module (BCM)
    • Instrument Panel Cluster (IPC)
    • Inflatable Restraint Sensing and Diagnostic Module (SDM)

Does the scan tool communicate with all of the control modules?

Go to Step 4

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

4

Select the display DTCs function on the scan tool for each of the following modules:

    • Body Control Module (BCM)
    • Electronic Brake Control Module (EBCM)
    • Engine Control Module (ECM)
    • Instrument Panel Cluster (IPC)
    • Inflatable Restraint Sensing and Diagnostic Module (SDM)

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Instrument Panel, Gages and Console

5

Does the scan tool display any DTCs which begin with a "U"?

Go to Diagnostic Trouble Code (DTC) List in Data Link Communications

Go to Step 6

6

Does the scan tool display DTC B1000, B1001, B1372, or B1382?

Go to Diagnostic Trouble Code (DTC) List in Body Control System

Go to Diagnostic Trouble Code (DTC) List