GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

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

The scan tool turns on.

Scan Tool Inoperative

2

  1. Turn the ignition switch on.
  2. Using scan tool, communicate with the Powertrain Control Module (PCM).

Communication is established between the scan tool and the PCM.

Scan Tool Does Not Communicate with Class 2 Data Line

3

Using scan tool, communicate with the Electronic Brake Traction Control Module (EBTCM).

Communication is established between the scan tool and the EBTCM.

Scan Tool Does Not Communicate with Class 2 Data Line

4

Using scan tool, communicate with the instrument cluster.

Communication is established between the scan tool and the instrument cluster.

Scan Tool Does Not Communicate with Class 2 Data Line

5

  1. If vehicle is not equipped with automatic climate control (RPO CJ2), skip to Step 6.
  2. Using scan tool, communicate with the Heater-A/C Control.

Communication is established between the scan tool and the Heater-A/C Control.

Scan Tool Does Not Communicate with Class 2 Data Line

6

Using scan tool, communicate with the Body Control Module (BCM).

Communication is established between the scan tool and the BCM.

Scan Tool Does Not Communicate with Class 2 Data Line

7

Using scan tool, communicate with the Supplemental Inflatable Restraint (SIR) system.

Communication is established between the scan tool and the SIR.

Scan Tool Does Not Communicate with UART Data Line

8

  1. If vehicle is not equipped with a CD player (RPO U1S), skip to Step 9.
  2. Using scan tool, communicate with the CD player.

Communication is established between the scan tool and the CD player.

Scan Tool Does Not Communicate with E and C Data Line

9

Using scan tool, communicate with the radio.

Communication is established between the scan tool and the radio.

Scan Tool Does Not Communicate with E and C Data Line

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