GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2001 🢒 Eldorado 🢒 Body and Accessories 🢒 Seats 🢒 Diagnostic System Check - Power Seat Systems

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 Table will determine the correct diagnostic procedure to use.

    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. This step determines if any internal controller DTCs are set.

    5.

  5. This steps determines if any system voltage DTCs are set.

Step

Action

Yes

No

1
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.

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:
    3. • Memory Seat Module (MSM)
    • Body Control Module (BCM)

Does the scan tool communicate with the Memory Seat 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

With a scan tool, select the display DTCs function for the Memory Seat Module.

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Seats

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 DTC B1656 or B1658?

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

Go to Step 7

7

Does the scan tool display DTC B1982 or B1983?

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

Go to Diagnostic Trouble Code (DTC) List