For 1990-2009 cars

### Circuit Description

The electronic brake control module (EBCM) controls the operation of the traction control system (TCS) indicator 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 indicator lamp OFF, the EBCM will ground the TCS indicator 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 indicator 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 indicator lamp, notifying the driver the brake system or DDRP needs to be serviced.

### Diagnostic Aids

Typical causes of the TCS indicator lamp inoperative with no DTCs set are as follows.

• | Faulty antilock brake system (ABS) warning lamp bulb/loose socket

• | F12 fuse open

• | Faulty EBCM

• | Grounded circuit between the EBCM and the cluster

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Component Connector End Views
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.
4. Connect the terminal 17 of the EBCM wiring harness connector and body ground with a jump wire.

Does the traction control system (TCS) indicator lamp turn ON?

--

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 resistance between terminal 17 of the EBCM wiring harness connector and terminal A13 of the cluster wiring harness connector.

Does the resistance measure less than the specified value?

2 Ω

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 | --