GM Service Manual Online
For 1990-2009 cars only

Object Number: 490170  Size: MF
Antilock Brake System Component Views
Antilock Brake System Schematics
Instrument Cluster: Analog Schematics
Data Link Connector Schematics
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

The instrument panel cluster (IPC) turns the ABS indicator on during the IPC bulb check for approximately 3 seconds when the ignition switch is turned to the RUN position. If the electronic brake control module (EBCM) sets a Diagnostic Trouble Code (DTC) the EBCM sends a class 2 message to the IPC to command the ABS indicator 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 Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

ABS Indicator On with No DTC Set

Step

Action

Value(s)

Yes

No

DEFINITION: ABS indicator does not turn off after the instrument panel cluster (IPC) bulb check. No ABS/TCS DTC(s) are set.

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Select the Body menu and then Instrument Cluster (IPC) on the scan tool.
  5. Select Lamp Test under Special Functions.
  6. With the scan tool, turn the warning indicators ON and then OFF

Does the ABS WARNING indicator turn ON and then OFF?

--

Go to Step 3

Go to Step 4

3

Replace the electronic brake control module (EBCM). Refer to Electronic Brake Control Module Replacement .

Did you complete the repair?

--

Go to Diagnostic System Check - ABS

--

4

Replace the instrument cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Did you complete the repair?

--

Go to Diagnostic System Check - ABS

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