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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Diagnostic System Check

Circuit Description

The ABS Diagnostic System Check is an organized approach to identifying problems associated with the EBCM. This must be the starting point for any ABS related concern and will direct you to the next logical step in diagnosing a malfunction. Most system malfunctions are linked to faulty wiring, connections and occasionally, to components. Understanding the ABS system and using the diagnostic tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Lack of communication may be due to a malfunction of the UART serial data circuit (EBCM) or a partial or total malfunction of the class 2 serial data circuit (PCM/VCM).

    2.

  2. The presence of DTCs that begin with a "U" indicates that some other module is not communicating. The specified procedure will compile all of the available information before tests are performed.

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. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the following control modules.
    3. • 4WAL 3 Sensor
    • Powertrain

Does the scan tool communicate with the control modules listed above?

--

Go to Step 3

Go to Scan Tool Does Not Communicate with UART Data Line (EBCM) or Scan Tool Does Not Communicate with Class 2 Device (PCM/VCM) in Data Link Communications

3

Select the display DTCs function on the scan tool for the following control modules.

    • 4WAL 3 Sensor
    • Powertrain

Does the scan tool display any DTCs for the control modules listed above?

--

Go to Step 4

Go to Symptoms

4

Does the scan tool display any DTCs that begin with a "U"?

--

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

Go to Step 5

5

Does the scan tool display DTC P0500, P0601, P0602, P0603, P0604, P0605, P0606, P1381 or P1621?

--

Go to Diagnostic Trouble Code (DTC) List/Type in Engine Controls - 4.3L, Diagnostic Trouble Code (DTC) List/Type in Engine Controls - 5.0L and 5.7L, Diagnostic Trouble Code (DTC) List/Type in Engine Controls - 6.5L (L65) or Diagnostic Trouble Code (DTC) List/Type in Engine Controls - 7.4L.

Go to Diagnostic Trouble Code (DTC) List/Type