GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

With the scan tool connected to the diagnostic link connector, make contact with any of the modules applicable to the vehicle.

Communication can be established.

Scan Tool Does Not Communicate with Components

2

Access the DTC's using the scan tool.

No DTC's found.

The module(s) listed will have DTC's present.

Refer to appropriate DTC list.

3

  1. Establish communication with the sensing diagnostic module (SDM).
  2. Access DTC's using the scan tool.

No DTC's found.

No communication with the sensing diagnostic module, or diagnostic link connector. Refer to Scan Tool Does Not Communicate With SDM

4

  1. Establish communication with the Electronic Brake Control Module (EBCM)
  2. Access DTC's using the scan tool.

No DTC's found.

No communication with the EBCM, or diagnostic link connector.

Refer to Scan Tool Does Not Communicate With EBCM.

5

  1. Establish communication with the powertrain control module (PCM).
  2. Access DTC's using the scan tool.

No DTC's found.

No communication with the PCM, or diagnostic link connector.

Refer to:

    • Scan Tool Does Not Communicate With UART Data Line
    • Scan Tool Does Not Communicate With Class 2 Serial Data Line

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