Test B1 EBCM/EBTCM Power/Ground Test

Antilock Brake System Traction Control System Wiring Diagram:

B1: EBCM/EBTCM Power And Ground Test:

OPERATION:
When the ignition switch is first turned to RUN, the EBCM/EBTCM goes through a self-check lasting 2-4 seconds. During this test, the EBCM/EBTCM grounds terminal 34, energizing the main relay. Once the self-check is completed, the main relay remains energized and delivers battery voltage to both the EBCM/EBTCM and the pressure modulator valve (PMV) assembly during vehicle operation. The constant voltage supply allows the vehicle to enter ABS mode without delay. The main relay is de-energized whenever the amber ANTILOCK indicator lights due to a system fault, causing the ABS system to shut down.

DTC 45 sets when the ignition switch is at run and battery voltage is detected at neither the PMV assembly nor EBCM/EBTCM terminals 20, 3 and/or 33. DTC 45 also sets when the EBCM/EBTCM detects an open or a short to ground in the LH inlet valve circuit.

POSSIBLE CAUSES:
Open CKT 650, 855, 858, 1077 or 1443.
Short to ground in CKT 858, 1077 or 1443.
Main relay fails open.
See Electrical Schematic Part 1 of 3 to CKT 803 at Main Relay