GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Catera 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 Diagnostic System Check - Cruise Control

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 malfunction of the Keyword serial data circuit. The specified procedure will determine the particular condition.

    2.

  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 Engine Control Module (ECM).

Does the scan tool communicate with the ECM?

Go to Step 3

Go to Scan Tool Does Not Communicate with Keyword 82 Data Line in Data Link Communications

3

Select the ECM DTCs function on the scan tool.

Does the scan tool display any of the following DTCs?

    • P0571
    • P0603
    • P1662

Go to DTC List in Engine Controls

Go to Step 4

4

Does the scan tool display any DTCs which begin with a "U"?

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

Go to Symptoms