For 1990-2009 cars

### Circuit Description

The electronic brake control module (EBCM) controls the operation of the traction control system (TCS) lamp. Battery voltage is supplied to the instrument panel (I/P) cluster terminal B14 when the ignition switch is turned ON. EBCM terminals 9 and 25 are hot at all times.

When the EBCM commands the TCS lamp OFF, the EBCM will ground the TCS lamp control circuit. This causes the lamp driver module (LDM) to open the path to ground for the bulb.

When the ignition switch is turned to the ON position, the EBCM turns ON the TCS lamp for 3 seconds for a bulb check.

Whenever a malfunction is detected within the general brake system or de-coupled dynamic rear proportioning (DDRP), the EBCM turns ON the TCS lamp, notifying the driver the brake system or DDRP needs to be serviced.

### Diagnostic Aids

The typical cause of the TCS lamp ON with no DTCs set is mainly EBCM wiring harness short to battery.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn the ignition switch OFF.
2. Disconnect the electronic brake control module (EBCM) wiring harness connector.
3. Turn the ignition switch ON.

Is the traction control system (TCS) lamp turned OFF?

--

Go to Step 3

Go to Step 4

3 | Replace the EBCM. Did you complete the replacement? | -- | System OK | --
4 |

1. Turn the ignition switch OFF.
2. Remove the cluster.
3. Measure the voltage between terminal A13 of the cluster wiring harness connector and body ground.

Does the voltage measure less than the specified value?

0.1 V

Go to Step 6

Go to Step 5

5 | Repair the short of wiring harness and battery. Did you complete the repair? | -- | System OK | --
6 | Replace the cluster or the bulb. Did you complete the replacement? | -- | System OK | --