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.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1251

Open in Pump Motor Circuit

There is an open in the motor system circuit (motor input circuit).

  • Pump motor wire harness connection

  • Brake booster with accumulator pump assembly

  • Master cylinder solenoid (Skid control ECU)

CAUTION / NOTICE / HINT

Note:

When replacing the master cylinder solenoid, perform calibration (Click here).

Tip:

Remove the hydraulic brake booster assembly before the inspection (Click here).

PROCEDURE

  1. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS

    1. Remove the hydraulic brake booster assembly.

      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.

      Click here

      OK

      The harness is tightened to the specified torque.

      Torque

      2.9 N*m{ 30 kgf*cm , 26 in.*lbf }

      Result

      Result

      OK

      NG
    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. C173363C01

      *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

      Result

      Result

      OK

      NG
    NG

    REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY

    Click here

    OK

  3. RECONFIRM DTC

    1. Reassemble the hydraulic brake booster assembly.

      Click here

    2. Install the hydraulic brake booster assembly.

      Click here

    3. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    4. Check if the same DTC is output.

      Click here

      Result

      Result

      Proceed to

      DTC is not output

      A

      DTC is output

      B

      Chassis > ABS/VSC/TRC > Trouble Codes

    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    REPLACE MASTER CYLINDER SOLENOID

    Click here