GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The ABS Diagnostic System Check is an organized approach to identify problems associated with the EBCM. This check must be the starting point for any EBCM complaint, and will direct you to the next logical step in diagnosing the complaint. The EBCM is a very reliable component and is not likely the cause of the malfunction. Most system complaints are linked to faulty wiring, connectors, and occasionally to components. Understanding the ABS system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.

Step

Action

Value(s)

Yes

No

1

Install a scan tool.

Does the scan tool power up?

--

Go to Step 2

Go to Scan Tool Does Not Power Up In Data Link Communications

2

  1. Reconnect all previously disconnected components.
  2. Turn ON the ignition, with the engine OFF.
  3. Attempt to establish communications with the EBCM.

Does the scan tool communicate with the EBCM?

--

Go to Step 3

Go to Scan Tool Does Not Communicate with Class 2 Data Line In Data Link Communications

3

  1. With the scan tool, in ABS/TCS Special Functions in order to run the Automated Test.
  2. Select the ABS/TCS display DTC function on the scan tool.

Does the scan tool display any DTCs?

--

Go to Step 4

Go to Symptoms

4

Does the scan tool display any DTCs which begin with a U (i.e. DTC U1016, U1000 or U1300, U1301)?

--

Go to Scan Tool Does Not Communicate with Class 2 Data Line

Go to Diagnostic Trouble Code (DTC) List/Type For The Applicable DTC