GM Service Manual Online
For 1990-2009 cars only

Test Description

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

  1. The lack of communication may be caused by a partial or a total malfunction of the circuit containing the class 2 serial data. 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 will collect all the available information before tests are performed.

  3. The presence of ABS DTCs could cause the Tire Pressure Monitor (TPM) system to be disabled, which is controlled by the Electronic Brake Control Module (EBCM).

Step

Action

Yes

No

1

Install a scan tool.

Does the scan tool turn on?

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 EBCM.

Does the scan tool communicate with the EBCM?

Go to Step 3

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

3

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 4

4

Select the Diagnostic Trouble Codes (DTC) function on the scan tool .

Does the scan tool display any ABS DTCs?

Go to Diagnostic System Check - ABS in Antilock Brake System

System OK