GM Service Manual Online
For 1990-2009 cars only

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. 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.

  2. 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

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 body control module (BCM), the powertrain control module (PCM), the driver door module (DDM), and the passenger door module (PDM).

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

Go to Step 3

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

3

Select the control module display DTCs function on the scan tool for the BCM, PCM, DDM and the PDM.

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Theft Deterrent

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 P0601, P0602, P0604 or P0606?

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

Go to Step 6

6

Does the scan tool display DTC B0605 or B1000?

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

Go to Step 7

7

Does the scan tool display DTC B2282-B2285, P0562, P0563, P1637 or P1638?

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

Go to Diagnostic Trouble Code (DTC) List