GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Park Avenue 🢒 Body and Accessories 🢒 Body Control System 🢒 Diagnostic System Check - Door Systems

Test Description

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

  1. This step verifies that the modules controlling door functions can communicate on the class 2 serial data circuit.

    Lack of communication may be due to partial or total malfunction of the circuit, however, lack of communication may also be due to an unpowered or ungrounded module. The specified procedure will determine the particular condition. Enabling the headlamps in this step ensures that an ungrounded door module cannot use the switch illumination circuit as an alternate ground path, which could cause the DTC or malfunction to be intermittent and lead to misdiagnosis and unnecessary parts replacement.

    2.

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

    3.

  3. The presence of DTCs U1161, U1162 or U1170 indicate one or more of the door modules is not communicating on the power door serial data line.

    4.

  4. The presence of other DTCs which begin with "U" indicate some other system control 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 ON the ignition, with the engine OFF.
  2. Turn ON the headlamp switch.
  3. Attempt to establish communication with:
    4. • The driver door module (DDM)
    • The powertrain control module (PCM)

Does the scan tool communicate with the listed 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 Driver Door Module display DTCs function on the scan tool.

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Doors

5

Does the scan tool display DTCs U1161, U1162 or U1170?

Go to DTC U1161-U1163 or U1170

Go to Step 6

6

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 Step 7

7

Does the scan tool display DTC B1656?

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

Go to Step 8

8

Does the scan tool display DTC B1982 or B1983?

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

Go to Step 9

9

Does the scan tool display DTC B2240, B2241 or B2242?

Go to Diagnostic Trouble Code (DTC) List in Seats

Go to Step 10

10

Does the scan tool display any DTCs that begin with a "P"?

Go to Diagnostic Trouble Code (DTC) Type Definitions in Engine Controls - 3.8L

Go to Diagnostic Trouble Code (DTC) List