Diagnostic trouble code C1257 Land Cruiser

DESCRIPTION

INSPECTION PROCEDURE

CHECK PUMP MOTOR OPERATION

RECONFIRM DTC

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.

DTC Code DTC Detection Condition Trouble Area
C1257/57 There is an open in the motor system circuit (motor input circuit). Hydraulic brake booster pump motor circuit

Inspection procedure

NOTICE:

When replacing the master cylinder solenoid, perform zero point calibration .

1.CHECK PUMP MOTOR OPERATION

  1. Turn the ignition switch off.

  1. Disconnect the A24 skid control ECU connector.

  1. Depress the brake pedal more than 20 times.

  1. Turn the ignition switch to ON.

  1. Check pump motor operation.

    OK:

    Pump motor normally operates.

    Result
    Result Proceed to
    OK A
    NG LHD B
    RHD C
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
A  
   

2.RECONFIRM DTC

  1. Turn the ignition switch off.

  1. Reconnect the A24 skid control ECU connector.

  1. Turn the ignition switch to ON.

  1. Clear the DTC .

  1. Check if the same DTC is output .

    Result
    Result Proceed to
    DTC is not output A
    DTC is output LHD B
    RHD C
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
A  
   
USE SIMULATION METHOD TO CHECK