GM Service Manual Online
For 1990-2009 cars only

Test Description

The number below refers to the step number 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.

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 powertrain control module.

Does the scan tool communicate with the powertrain control module?

Go to Step 3

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

3

Select the powertrain control module display DTCs function on the scan tool.

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

Go to Diagnostic Trouble Code (DTC) Types 2.2L or Diagnostic Trouble Code (DTC) Types 2.4L

Go to Symptoms - Cruise Control