GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Avalanche - 2WD 🢒 Body and Accessories 🢒 Entertainment 🢒 Diagnostic System Check - Entertainment System

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. Uses the scan tool to determine if there are any codes in the radio module.

    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.

    4.

  4. The presence of DTCs that begin with the letter "B" indicates an issue with a module that communicates with BCM.

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:
    3. • Radio
    • Amplifier (1st design only)
    • Digital radio receiver
    • Rear seat entertainment if equipped

Does the scan tool communicate with the above modules?

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 following display DTCs function on the scan tool.

    • Radio
    • Amplifier
    • Digital radio receiver

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Entertainment

5

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

Go to Diagnostic Trouble Code (DTC) List in Data Link Communications

Go to Step 6

6

Does the scan tool display DTC B1000, B1004, B1007 or B1009?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 7

7

Does the scan tool display DTC B1327?

Go to Diagnostic Trouble Code (DTC) List

Go to Diagnostic Trouble Code (DTC) List