GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The traction control switch is a momentary switch. The signal circuit of the traction control switch is grounded when the driver presses the traction control switch. The traction control system will change state from traction on to traction off or from traction off to traction on each time the traction control switch is pressed. DTC C1312 checks the state of the TCS off switch lamp circuit.

Conditions for Setting the DTC

DTC C1312 can be set if the EBCM detects an open, short to ground or short to power on the TCS switch lamp circuit for 0.016 seconds.

Action Taken When the DTC Sets

The EBCM will store a code C1312 in history.

Conditions for Clearing the DTC

    • If the conditions, which set DTC C1312, are no longer present, using the scan tool clear the DTC.
    • Any DTC, which has not occurred in 100 drive cycles, will be cleared from history data.

Diagnostic Aids

Check for a traction control switch that may be sticking in the pressed position. For an intermittent condition refer to .

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step checks the traction control switch functions properly, and the EBCM control of the indicator.

  1. This step checks the traction control switch voltage supply circuit for an open or short to ground.

  1. This step checks the traction control switch lamp control circuit for a short to B+.

  1. This step checks the traction control switch lamp control circuit for an open or high resistance.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check

2

Turn ON the ignition, with the engine OFF.

Is the TCS switch indicator illuminated?

--

Go to Step 4

Go to Step 3

3

Press the traction ON/OFF switch.

Is the TCS switch indicator illuminated?

--

Go to Diagnostic Aids

Go to Step 5

4

Disconnect the EBCM.

Is the TCS switch indicator illuminated?

--

Go to Step 10

Go to Step 12

5

  1. Disconnect the TCS switch.
  2. Test the TCS voltage supply circuit for an open or short to ground. Refer to Testing for Short to Ground and Wiring Repairs in wiring systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 6

6

With a DMM, measure the voltage between the TCS switch voltage supply circuit and the TCS switch lamp control circuit. Refer to Troubleshooting with a Digital Multimeter in wiring system.

Does the voltage measure greater than the specified value?

11 v

Go to Step 11

Go to Step 7

7

Test the TCS switch lamp control circuit for a short to B+. Refer to Testing for a Short to Voltage and Wiring Repairs in wring systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 8

8

Test the TCS switch lamp control circuit for an open/high resistance. Refer to Testing for Continuity in wiring systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

9

Inspect for poor connections at the harness connector of the EBCM. Refer to Intermittents and Poor Connections Diagnosis and Wiring Repairs in wiring systems.

Did you correct the condition?

--

Go to Step 13

Go to Step 12

10

Repair the short to ground in the TCS switch lamp control circuit. Refer to Testing for Short to Ground and Wiring Repairs in wiring systems.

Is the repair complete?

--

Go to Step 13

--

11

Replace the TCS switch. Refer to Rear Window Wiper and Washer Switch Replacement in wiper/washer systems.

Did you complete the replacement?

--

Go to Step 13

--

12

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

Did you complete the replacement?

--

Go to Step 13

--

13

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 13

System OK