GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Diagnostic System Check - Theft Deterrent

Test Description

The number(s) below refer to the step number(s) 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. 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.

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 PZM, IPC and PCM.

Does the scan tool communicate with the PZM, IPC and PCM?

Go to Step 3

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

3

Select the PZM, IPC and PCM display DTCs functions on the scan tool.

Does the scan tool display any DTCs for the modules?

Go to Step 4

Go to Symptoms - Theft Deterrent

4

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 5

5

Does the scan tool display DTC B1556 or B1558?

Go to Diagnostic Trouble Code (DTC) List/Type in Instrument Panel, Gauges and Console or Diagnostic Trouble Code (DTC) List/Type Body Control System

Go to Step 6

6

Does the scan tool display DTC B1327, B1328 or B1981?

Go to Diagnostic Trouble Code (DTC) List/Type in Instrument Panel, Gauges and Console or Diagnostic Trouble Code (DTC) List/Type Body Control System

Go to Diagnostic Trouble Code (DTC) List/Type