C1257

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1257/57: Power Supply Drive Circuit

DTC C1257/57 - Power Supply Drive Circuit

DESCRIPTION

The motor relay (semiconductor relay) is built into the hydraulic brake booster and drives the pump motor based on a signal from the skid control ECU.






INSPECTION PROCEDURE
NOTE: When replacing the master cylinder solenoid, perform zero point calibration Programming and Relearning.

PROCEDURE

1. CHECK HYDRAULIC BRAKE BOOSTER PUMP MOTOR OPERATION
(a) Turn the ignition switch off.
(b) Disconnect the skid control ECU connector (A4).
(c) Depress the brake pedal more than 20 times.
(d) Turn the ignition switch to ON.
(e) Check the hydraulic brake booster pump motor operation.
OK:
Hydraulic brake booster pump operates.
NG -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY
OK -- Continue to next step.
2. RECONFIRM DTC
(a) Turn the ignition switch off.
(b) Reconnect the skid control ECU connector (A4).
(c) Turn the ignition switch to ON.
(d) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
Result:






B -- END
A -- REPLACE MASTER CYLINDER SOLENOID