Toyota 4Runner: Power Supply Drive Circuit (C1257)

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Power Supply Drive Circuit (C1257)

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.

DTC Code	DTC Detection Condition	Trouble Area
C1257	There is an open in the motor system circuit (motor input circuit).	Master cylinder solenoid (Skid control ECU)

CAUTION / NOTICE / HINT

NOTICE:

When replacing the master cylinder solenoid, perform calibration (See page ).

PROCEDURE

1.	CHECK PUMP MOTOR OPERATION

(a) Turn the ignition switch off.

(b) Disconnect the A6 skid control ECU connector.

(d) Turn the ignition switch to ON.

(e) Check pump motor operation.

OK:

Pump motor operates normally.

REPLACE MASTER CYLINDER SOLENOID

2.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Reconnect the A6 skid control ECU connector.

(d) Clear the DTCs (See page ).

(e) Turn the ignition switch off.

(f) Check if the same DTC is output (See page
).

Result

Result	Proceed to
DTC is output	A
DTC is not output	B

REPLACE MASTER CYLINDER SOLENOID

USE SIMULATION METHOD TO CHECK

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