GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Diagnostic System Check - Engine Electrical

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.

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

    3.

  3. The presence of DTCs which begin with "U" indicate some of the modules are not communicating.

    4.

  4. Tests for the presence of DTCs related to Starter and Generator control circuits, due to a wiring malfunction or system voltage being high or low. The specified procedure will determine the particular condition.

Step

Action

Yes

No

1

Did you perform the Battery Inspection/Test?

Go to Step 2

Go to Battery Inspection/Test

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 establish communication with the follwoing modules:
    3. • Instrument Panel Cluster (IPC)
    • Powertrain Control Module (PCM)
    • Body Control Module (BCM)

Does the scan tool communicate with the modules?

Go to Step 4

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

4

Select the IPC, PCM, and BCM display DTC function on the scan tool.

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Engine Electrical

5

Does the scan tool display any DTCs which begin with 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 P0560, P0562, P0563, P0615, P0621, or P0622?

Go to Diagnostic Trouble Code (DTC) List/Type in Engine Controls - 4.6L

Go to Step 7

7

Does the scan tool display DTC B1981, B1982 or B1983?

Go to Diagnostic Trouble Code (DTC) List/Type in Instrument Panel Gauges and Console

Go to Step 8

8

Does the scan tool display DTC B2710, B2711, B2719, B2750, B2780, B2780, B2781, B2782, or B2783?

Go to Diagnostic Trouble Code (DTC) List/Type in Theft Deterrent

Go to Step 9

9

Does the scan tool display DTC B1910 or B1911?

Go to Diagnostic Trouble Code (DTC) List/Type

System OK