GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Envoy - 2WD 🢒 Body and Accessories 🢒 Instrument Panel, Gages, and Console 🢒 Diagnostic System Check - Audible Warnings

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 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 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 the ignition ON, with the engine OFF.
  2. Attempt to establish communication with the following control modules:
    3. • Audio Amplifier (w/UQA)
    • Body Control Module (BCM)
    • Instrument Panel Cluster (IPC)
    • Radio

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:

    • Audio Amplifier (w/UQA)
    • Body Control Module (BCM)
    • Instrument Panel Cluster (IPC)
    • Radio

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Instrument Panel, Gages and Console

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 B1000, B1397, or B1440?

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

Go to Diagnostic Trouble Code (DTC) List