GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Astro - 2WD 🢒 Body and Accessories 🢒 Data Link Communications 🢒 Diagnostic System Check - Data Link Communications

Test Description

  1. This step is to determine whether the scan tool can be powered up.

    2.

  2. This step is to check the Class 2 communications system for connections and any DTCs that may be set.

    3.

  3. This step is to determine if the scan tool can communicate with the UART Data Line, specifically with in the Supplemental Inflation Restraint System.

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

With scan tool connected make contact with any of the modules applicable to the vehicle

Scan Tools main menu.
    • Blank Screen
    • No power to the scan tool

Refer to Scan Tool Inoperative

2

Select Diagnostics Circuit Check, Class 2 DTC Check from the scan tools menu.

No DTC's found.

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

    • No Communication with the vehicle, or Diagnostic Link Connector. Refer to Scan Tool Does Not Communicate with Class 2 Data Line

3

  1. Select Body Diagnostics from the scan tools menu.
  2. Select SIR UART Data Line information.
  3. Access DTC's using the scan tool.

No DTC's found.

No communication with the vehicle, or Diagnostic Link Connector. Refer to Scan Tool Does Not Communicate with UART Data Line

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