Circuit Description
The electronic brake control module (EBCM) controls the operation of the traction control system (TCS) active 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 active lamp OFF, the EBCM will ground the TCS active 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 active 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 |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Does the traction control system (TCS) active lamp turn ON? | -- | Go to Step 3 | Go to Step 4 |
3 | Replace the EBCM. Did you complete the replacement? | -- | System OK | -- |
4 |
Does the resistance measure less than the specified value? | 2 ohms | Go to Step 6 | Go to Step 5 |
5 | Repair the wiring harness. Did you find and correct the condition? | -- | System OK | -- |
6 | Replace the cluster or the bulb. Did you complete the replacement? | -- | System OK | -- |
