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 partial malfunction of the serial data circuit or due to a total malfunction of the serial data circuit. The specified procedure will determine the particular condition.

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

  3. The presence of ABS DTCs indicate that the EBCM requested illumination of the red Brake indicator due to a concern in the ABS system. The presence of DTCs other than those listed are not related to this system.

Step

Action

Yes

No

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 ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the following control modules:
  3. • Driver information center (DIC)
    • Electronic brake control module (EBCM)
    • Instrument panel cluster (IPC)

Does the scan tool communicate with all control modules?

Go to Step 3

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

3

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

    • Driver information center (DIC)
    • Electronic brake control module (EBCM)
    • Instrument panel cluster (IPC)

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Hydraulic Brakes

4

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

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

Go to Step 5

5

Does the scan tool display DTC B1004 or B1007?

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

Go to Step 6

6

Does the scan tool display DTC B1327, B1513, or B1514?

Go to Diagnostic Trouble Code (DTC) List in Engine Electrical

Go to Diagnostic Trouble Code (DTC) List in Antilock Brake System