C1257

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1257: Power Supply Drive Circuit
C1257 - 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

NOTICE:
* When replacing the master cylinder solenoid, perform zero point calibration Calibration.
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. CHECK HYDRAULIC BRAKE BOOSTER PUMP MOTOR OPERATION

(a) Turn the ignition switch off.

(b) Disconnect the skid control ECU connector.

(c) Depress the brake pedal more than 40 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 MASTER CYLINDER SOLENOID Disassembly
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 output Reading and Clearing Diagnostic Trouble Codes.

Result





B -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

A -- REPLACE MASTER CYLINDER SOLENOID Disassembly