GM Service Manual Online
For 1990-2009 cars only

Object Number: 262063  Size: MF
ABS Components
ABS/TCS Schematics

Circuit Description

The TC indicator is controlled by the EBTCM. The EBTCM supplies the ground to the TC indicator circuit to turn the indicator on. When the TC indicator circuit is not grounded at the EBTCM, the TC indicator remains off. When the EBTCM sees the traction control switch voltage go low, it turns the TC indicator on and disables traction control. The EBTCM harness connector contains a shorting bar for the TC indicator circuit. When the EBTCM connector is disconnected from the EBTCM, the shorting bar shorts the TC indicator terminal to ground turning on the indicator.

Diagnostic Aids

If the EBTCM harness connector is not securely connected to the EBTCM, the shorting bar in the harness connector may turn on the TC indicator. Make sure the EBTCM harness connector is securely connected to the EBTCM.

    • 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 Diagnostic Procedures 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 EBTCM malfunction. You must install the pinout box and cable adapter to the harness connector at this point to prevent the shorting bar in the harness connector from grounding the circuit and turning on the indicator.

  2. This step checks for a short to ground in CKT XB105.

Traction Control Indicator Always On No DTC

Step

Action

Value(s)

Yes

No

DEFINITION: TC indicator is on and traction control was not turned off. There are no DTC(s) set.

1

Was the Diagnostic System Check performed?

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Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch to the RUN position, engine off.
  2. Using a scan tool enter ABS/TCS Data List.
  3. While monitoring the TCS Switch State, press and hold the TCS On/Off switch for three seconds, then release the TCS On/Off switch.

Does the switch state change from Off to On as the TCS switch is pressed and released?

--

Go to Step 3

Go to Step 8

3

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBTCM connector C1.
  3. Install the J 39700 Universal Pinout Box using the J 39700-280 cable adapter to connector C1 only.
  4. Turn the ignition switch to the RUN position, engine off.

Does the TC Indicator turn off?

--

Go to Step 4

Go to Step 5

4

Replace the EBTCM. Refer to Electronic Brake and Traction Control Module Replacement .

Is the replacement complete?

--

Go to Diagnostic System Check - ABS

--

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the Instrument Cluster connector.
  3. Using J 39200 DMM, measure the resistance between terminals 20 and 19 of J 39700 .

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

OL (infinite)

Go to Step 7

Go to Step 6

6

Repair CKT XB105 for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

7

Suspect the Instrument Cluster. Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

8

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBTCM connector C1.
  3. Install the J 39700 Universal Pinout Box using the J 39700-280 cable adapter to connector C1 only.
  4. Using J 39200 DMM, measure the resistance between terminals 31 and 19 of J 39700 .

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

OL (Infinite)

Go to Step 4

Go to Step 9

9

Repair CKT XA105 for an Short to Ground, being sure to check the traction control switch for a short. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

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