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

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.

    • DTC U1016. Refer to DTC U1016 PCM Class 2 Serial Data Line Fault .
    • DTC U1041. Refer to DTC U1041 Loss of EBCM Communication .
    • DTC U1192. Refer to DTC U1192 Loss of VTD Class 2 Serial Data Com .
    • DTC U1193. Refer to DTC U1193 Loss of VIM Class 2 Communication .
    • DTC U1255. Refer to DTC U1255 Class 2 Communication Malfunction .
    • No Communication with the vehicle or with the diagnostic link connector. Refer to Scan Tool Does Not Communicate with Class 2 Data Line or Scan Tool Does Not Communicate with Components .

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 with the diagnostic link connector. Refer to Scan Tool Does Not Communicate with UART Data Line .

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 vehicle or with the diagnostic link connector. Refer to Scan Tool Does Not Communicate with Electronic Brake Control Module .

5
  1. Establish communication with the powertrain control system(s).
  2. Access DTC's using the scan tool.

No DTC's found.

No communication with the vehicle or the diagnostic link connector. Refer to Scan Tool Does Not Communicate with Vehicle Control Module/Powertrain Control Module .

or

Scan Tool Does Not Communicate with Vehicle Control Module/Powertrain Control Module .

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