Diagnostic System Check - Instrument Cluster. Buick GL7 (Export) 2000

For 1990-2009 cars

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

3. The presence of DTCs which begin with "U" indicate that loss of Class 2 communications has occurred.

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:

• | Instrument Panel Cluster (IPC)

• | Powertrain Control Module (PCM)

Does the scan tool communicate with the control modules listed above?

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:

• | Instrument Panel Cluster (IPC)

• | Powertrain Control Module (PCM)

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms

4 | Does the scan tool display any other DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Diagnostic Trouble Code (DTC) List/Type