GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The ABS indicator is controlled by the EBCM. The EBCM supplies the ground to ABS indicator control circuit in order to keep the indicator off. When ABS indicator control circuit looses ground at the EBCM, the ABS indicator turns on.

Diagnostic Aids

    • It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
    • Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
       - Backed out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Poor terminal-to-wiring connections
       - Physical damage to the wiring harness
    • The following conditions may cause an intermittent malfunction:
       - A poor connection
       - Rubbed-through wire insulation
       - A broken wire inside the insulation
    • If an intermittent malfunction exists refer to General Electrical Diagnosis in Wiring Systems for further diagnosis.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks for an internal EBCM malfunction.

  2. This step checks for a short to ground in ABS indicator control circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBCM connector C1.
  3. Turn the ignition switch to the RUN position.

Does the ABS Indicator come on?

--

Go to Step 3

Go to Step 4

3

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Is the replacement complete?

--

Go to Step 9

--

4

  1. Turn the ignition switch to the OFF position.
  2. Install the J 39700 Universal Pinout Box using the J 39700-530 cable adapter to connector C1 only.
  3. Disconnect the Instrument Cluster connector C1.
  4. Using J 39200 DMM, measure the resistance between terminals 16 and 15 of J 39700 .

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 6

Go to Step 5

5

Repair ABS indicator control circuit for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 9

--

6

  1. Turn the ignition switch to the OFF position
  2. Check the ABS indicator bulb. Refer to Instrument Cluster Indicator Lamp Replacement in Instrument Panel, Gauges and Console.

Is the ABS Indicator bulb OK?

--

Go to Step 8

Go to Step 7

7

Replace the ABS Indicator Bulb. Refer to Instrument Cluster Indicator Lamp Replacement in Instrument Panel, Gauges and Console.

Is the replacement complete?

--

Go to Step 9

--

8

Replace the Instrument Panel Cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the replacement complete?

--

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2