GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Turn the ignition switch to the LOCK position.
  2. Connect the scan tool to the Data Link Connector (DLC).
  3. Turn on the scan tool.

The scan tool turns on.

Scan Tool Does Not Communicate with Components

2

  1. Turn the ignition switch to the RUN position.
  2. Use the scan tool in order to communicate with the PCM, EBCM, IC, SIR, BCM, and HVAC.

Communication is established between the scan tool and all models.

Scan Tool Does Not Communicate with Class 2 Data Line

3

Use the scan tool in order to communicate with the radio or the mobile telephone handset

Communication is established between the scan tool and the radio or the mobile telephone handset.

Scan Tool Does Not Communicate with E and C Data Line

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.