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 master cylinder solenoid 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 PUMP MOTOR OPERATION
(a) Turn the ignition switch off.
(b) Disconnect the skid control ECU (S28) connector.
(c) Depress the brake pedal more than 20 times.
(d) Turn the ignition switch to ON.
(e) Check pump motor operation.
OK:
Pump motor normally operates.

NG -- REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
OK -- Continue to next step.

2. RECONFIRM DTC
(a) Turn the ignition switch off.
(b) Reconnect the skid control ECU connector.
(c) Turn the ignition switch to ON.
(d) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(e) Check if the same DTC is detected Reading and Clearing Diagnostic Trouble Codes.
Result:





B -- CHECK FOR INTERMITTENT PROBLEMS
A -- REPLACE MASTER CYLINDER SOLENOID