ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1251

DTC Code DTC Name
C1251 Open in Pump Motor 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 (master cylinder solenoid).

DTC Code DTC Detection Condition Trouble Area
C1251 There is an open in the motor system circuit (motor input circuit).

  • Pump motor wire harness connection

  • Brake booster with accumulator pump assembly

  • Skid control ECU (Master cylinder solenoid)

INSPECTION PROCEDURE

Note

After replacing the master cylinder solenoid, perform zero point calibration Click here.

Tech Tips

Remove the hydraulic brake booster assembly before the inspection (for LHD: Click here, for RHD: Click here.

PROCEDURE


  1. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS


    1. Remove the hydraulic brake booster assembly (for LHD: Click here, for RHD: Click here.

    2. Check the tightening torque of the 2 screws which secure the wire harness connecting the master cylinder solenoid and brake booster with accumulator pump assembly (for LHD: Click here, for RHD: Click here.

      OK
      The harness is tightened to the specified torque.

    NG

    RETIGHTEN SCREWS

    OK

  2. CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS


    1. Using a screwdriver, remove the 2 screws and pull out the wire harness from the master cylinder solenoid.

    2. A0159NIE03
      Text in Illustration
      *1 Pump motor wire harness
      *a Red wire
      *b Black wire

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      Red wire terminal - Black wire terminal Always Below 2 Ω

      Tech Tips


        Refer to the brake booster with accumulator pump assembly installation procedures:

      • for LHD Click here

      • for RHD Click here


    NG

    REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

    OK

  3. RECONFIRM DTC


    1. Reassemble the hydraulic brake booster assembly (for LHD: Click here, for RHD: Click here.

    2. Install the hydraulic brake booster assembly (for LHD: Click here, for RHD: Click here.

    3. Clear the DTCs Click here.

    4. Turn the ignition switch off.

    5. Check if the same DTC is output Click here.

      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 Click here

    C

    REPLACE MASTER CYLINDER SOLENOID Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here