Capacitor Malfunction - Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1377/43: Capacitor Malfunction

DTC C1377/43 - Capacitor Malfunction

DESCRIPTION

The brake control power supply (capacitor) provides auxiliary power for brake control when the auxiliary battery (12 V) voltage drops.






WIRING DIAGRAM













INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (ABS MAIN3)




(a) Remove the ABS MAIN3 fuse from the engine room relay block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- CHECK FOR SHORT IN ALL HARNESS AND CONNECTOR CONNECTED TO FUSE AND REPLACE FUSE
OK -- Continue to next step.

2. CHECK BRAKE CONTROL POWER SUPPLY (BC VOLTAGE)




(a) Measure the voltage of the connector.
HINT: Measure the voltage from behind the connector with the connector connected.

Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

3. CHECK SKID CONTROL ECU (+BI1, +BI2 VOLTAGE)




(a) Measure the voltage of the connectors.
HINT: Measure the voltage from behind the connector with the connector connected to the skid control ECU.

Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

4. CHECK SKID CONTROL ECU (+BO1, +BO2 VOLTAGE)




(a) Measure the voltage of the connectors.
HINT: Measure the voltage from behind the connector with the connector connected to the skid control ECU.

Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. CHECK BRAKE CONTROL POWER SUPPLY (OUT, BCTY, OUT2 VOLTAGE)




(a) Measure the voltage of the connector.
HINT: Measure the voltage from behind the connector with the connector connected.

Standard voltage:






NG -- REPLACE BRAKE CONTROL POWER SUPPLY
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR