VEHICLE STABILITY CONTROL 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).

  • ABS NO. 1 fuse

  • Pump motor wire harness connection

  • Brake booster with accumulator pump assembly

  • Skid control ECU (Master cylinder solenoid)

WIRING DIAGRAM

Refer to DTC C1253 Click here.

CAUTION / NOTICE / HINT

Note


  • After replacing the master cylinder solenoid, perform zero point calibration and store the system information Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

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

PROCEDURE


  1. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS


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

      OK
      The harness is tightened to the specified torque.

    NG

    RETIGHTEN SCREWS

    OK

  2. CHECK HARNESS AND CONNECTOR (+BM1/+BM2 TERMINAL)


    1. Turn the engine switch off.

    2. Disconnect the skid control ECU (master cylinder solenoid) connectors.

    3. B001B2RE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Master Cylinder Solenoid])

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A24-2 (+BM1) - Body ground Always 11 to 14 V
      A25-2 (+BM2) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (GND1, GND2 AND GND3 TERMINAL)


    1. B0018RYE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Master Cylinder Solenoid])

      Turn the engine switch off.

    2. Disconnect the skid control ECU (master cylinder solenoid) connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A24-1 (GND1) - Body ground Always Below 1 Ω
      A24-32 (GND2) - Body ground Always Below 1 Ω
      A25-4 (GND3) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. 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. B0019NXE03
      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

  5. RECONFIRM DTC


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

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

    3. Clear the DTCs Click here.

    4. Turn the engine 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

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE MASTER CYLINDER SOLENOID Click here

    C

    REPLACE MASTER CYLINDER SOLENOID Click here