GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 Envoy - 2WD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Diagnostic System Check - Instrument Cluster

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

    3.

  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 the ignition ON, with the engine OFF.
  2. Attempt to establish communication with the following control modules:
    3. • Body Control Module (BCM)
    • Driver Door Module (DDM)
    • Electronic Brake Traction Control Module (EBTCM)
    • Inflatable Restraint Diagnostic Module (SDM)
    • Instrument Panel Cluster (IPC)
    • Liftgate Module (LGM)
    • Passenger Door Module (PDM)
    • 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

Important:: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.

  1. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool.
  2. Rotate the ignition switch through all positions while observing the Ignition Switch Power Mode parameter.

Does the Ignition Switch parameter reading match the ignition switch position for all switch positions?

Go to Step 4

Go to Power Mode Mismatch in Body Control System

4

Select the display DTCs function on the scan tool for the following control modules:

    • Body Control Module (BCM)
    • Driver Door Module (DDM)
    • Electronic Brake Traction Control Module (EBTCM)
    • Inflatable Restraint Diagnostic Module (SDM)
    • Instrument Panel Cluster (IPC)
    • Liftgate Module (LGM)
    • Passenger Door Module (PDM)
    • Powertrain Control Module (PCM)

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Instrument Panel, Gages and Console

5

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 6

6

Does the scan tool display B1000 or B1440?

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

Go to Step 7

7

Does the scan tool display DTC P0562, P0563, P0621, or P0622?

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

Go to Diagnostic Trouble Code (DTC) List