GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Avalanche - 4WD 🢒 Body and Accessories 🢒 Retained Accessory Power 🢒 Diagnostic System Check - Retained Accessory Power

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the retained accessory power (RAP) power mode function is malfunctioning by checking functions internally enabled by the body control module (BCM).

    2.

  2. The BCM sends class 2 messages to other control modules via the serial data link, allowing them to operate in RAP power mode. 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.

    3.

  3. This step is analyzing the BCM for DTCs.

    4.

  4. The presence of DTCs that begin with "U" indicate another module is not communicating. The specified procedure will compile all the available information before tests are performed.

Step

Action

Yes

No

Schematic Reference: Retained Accessory Power (RAP) Schematics

1

  1. Turn key to the ON position.
  2. Close all vehicle doors.
  3. Turn key to the OFF position.
  4. Attempt to operate all of the following functions that are equipped on the vehicle:
    5. • Sunroof
    • Right and left rear power windows
    • Right and Left rear quarter power vent windows

Are all of the accessories inoperative?

Go to Step 2

Go to Control Module References in Body Control System for the applicable Diagnostic System Check for the system that does not operate

2

Install a scan tool.

Does the scan tool power up?

Go to Step 3

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

3

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to communicate with the body control module (BCM).

Does the scan tool communicate with the BCM?

Go to Step 4

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

4

Select the body control module display DTCs function on the scan tool.

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Retained Accessory Power

5

Do any of the DTCs begin with a "U"?

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

Go to Step 6

6

Compare the DTCs listed below to the scan tool:

    • B1000-Refer to DTC B1000 .
    •  B1440-Refer to DTC B1440 .

Are any of the DTCs shown on the scan tool?

Go to the appropriate DTC diagnostic table

Go to Control Module References in Body Control System for the applicable sub-section/DTC procedure