GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 GL7 (Export) 🢒 Body and Accessories 🢒 Data Link Communications 🢒 Diagnostic System Check - Engine Electrical

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.

  2. The symptom list in Symptoms will determine the correct diagnostic procedure to use.

    3.

  3. 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

Did you perform the Battery Inspection/Test?

Go to Step 2

Go to Battery Inspection/Test

2
  1. Install a scan tool
  2. Turn ON the ignition, with the engine OFF.

Does the scan tool power up?

Go to Step 3

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

3

Attempt to establish communication with the following components:

    • Powertrain Control Module (PCM)
    • Vehicle Theft Deterrent Module (VTD)

Does the scan tool communicate with the PCM and VTD?

Go to Step 4

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

4

Select the PCM and VTD display DTC function on the scan tool.

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Engine Electrical

5

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

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

Go to Step 6

6

Does the scan tool display any DTCs in the PCM which begin with P?

Go to Diagnostic Trouble Code (DTC) List/Type in Engine Controls - 3.0L (LW9)

Go to Step 7

7

Does the scan tool display any DTCs in the VTD which begin with B?

Go to Diagnostic Trouble Code (DTC) List/Type in Theft Deterrent

System OK