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For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2007 🢒 H2 🢒 Brakes 🢒 Antilock Brake System 🢒 Traction Off Indicator Always On

Circuit Description

The traction control system (TCS) TRAC OFF indicator is controlled by the instrument panel cluster (IPC) via class 2 serial data messages from the electronic brake control module (EBCM). When the EBCM sees the TCS switch fault, the EBCM then disables the TCS and sends a message to the IPC to turn the TRAC OFF indicator ON. Each time the ignition is cycled from OFF to ON, the TCS is enabled.

The following conditions will cause the TRAC OFF indicator to illuminate:

    • The EBCM has disabled the TCS due to a DTC.
    • The EBCM has disabled the TCS due to a overheated ABS/TCS hydraulic unit.
    • The IPC bulb check. When the ignition switch is turned to ON, the TRAC OFF indicator will turn ON for approximately 5 seconds and then turn OFF.

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 Inducing Intermittent Fault Conditions .

Test Description

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

  1. Checks if the scan tool can turn ON and OFF all the indicator lamps in the IPC.

  1. Checks if the circuits going to the IPC or the IPC is at fault.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Using a scan tool, select the instrument panel cluster (IPC) Special Functions mode.
  2. Go to Displays Test in Output Control.
  3. In the Displays Test mode you can turn ON or OFF the instrument panel indicators.

    4. All indicators will turn ON when commanded ON.

Does the TRAC OFF indicator turn ON then OFF?

Go to Step 3

Go to Step 4

3

Replace the electronic brake control module (EBCM). Refer to Control Module References for replacement, setup, and programming.

Is the replacement complete?

Go to Diagnostic System Check - Vehicle

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4

  1. Disconnect the IPC and connect a Test Light across the appropriate power and ground terminals.
  2. Test Light OFF, repair open in power or ground circuit to IPC.
  3. Test Light ON, check connector for poor connection to IPC.
  4. If OK, replace the IPC. Refer to Control Module References for replacement, setup, and programming.

Is the IPC replacement complete?

Go to Diagnostic System Check - Vehicle

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