Dtc C1257 Power Supply Drive Circuit


DESCRIPTION

INSPECTION PROCEDURE

CHECK PUMP MOTOR OPERATION

RECONFIRM DTC

DTC C1257 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.

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)

INSPECTION PROCEDURE

NOTICE:
When replacing the master cylinder solenoid, perform calibration (LandCruiser RM00000452J00ZX.html).
1.CHECK PUMP MOTOR OPERATION

  1. Turn the ignition switch off.

  1. Disconnect the A7 skid control ECU connector.

  1. Depress the brake pedal more than 40 times.

  1. Turn the ignition switch to ON.

  1. Check pump motor operation.

    OK:
    Pump motor operates normally.
    Result
    Result
    		Proceed to
    OK
    		A
    NG (for LHD)
    		B
    NG (for RHD)
    		C


B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A


2.RECONFIRM DTC

  1. Turn the ignition switch off.

  1. Reconnect the A7 skid control ECU connector.

  1. Turn the ignition switch to ON.

  1. Clear the DTCs (LandCruiser RM0000046KV016X.html).

  1. Check if the same DTC is output (LandCruiser RM0000046KV016X.html).

    Result
    Result
    		Proceed to
    DTC is not output
    		A
    DTC is output (for LHD)
    		B
    DTC is output (for RHD)
    		C



B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A

USE SIMULATION METHOD TO CHECK (LandCruiser RM000003YMJ00XX.html)