ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1251/51

DTC Code DTC Name
C1251/51 Open in Pump Motor Circuit

DESCRIPTION

DTC Code DTC Detection Condition Trouble Area
C1251/51 Actuator pump motor does not operate properly.

  • Brake actuator assembly (Ground circuit)

  • Brake actuator assembly (Motor circuit)

  • Skid control ECU

WIRING DIAGRAM

Refer to DTCs C0273/13 and C0274/14 Click here.

INSPECTION PROCEDURE

Tech Tips

When C0273/13 and/or C0274/14 is output together with C1251/51, inspect and repair the trouble areas indicated by C0273/13 and/or C0274/14 first Click here.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (ABS MOTOR RELAY)


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine.

    4. Select the Active Test mode on the intelligent tester Click here.

      ABS / VSC / TRC:
      Tester Display Test Part Control Range Diagnostic Note
      ABS Motor Relay ABS motor relay Relay ON / OFF Operating sound of motor can be heard

    5. Check the operating sound of the ABS motor when operating it with the intelligent tester.

      OK
      The operating sound of the ABS motor can be heard.
      Result
      Result Proceed to
      The operating sound is not heard A
      The operating sound is heard B

    B

    RECONFIRM DTC Click here

    A

  2. INSPECT BRAKE ACTUATOR ASSEMBLY (GND TERMINAL)


    1. A01CH7OE01

      Turn the ignition switch off.

    2. Disconnect the brake actuator connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      S22-1 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  3. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Reconnect the brake actuator connector.

    3. Clear the DTC (See Pub. No. RM1008E, page 05-195).

    4. Start the engine.

    5. Drive the vehicle at a speed of 20 km/h (12 mph) or more for 30 seconds or more.

    6. Check if the same DTC is recorded (See Pub. No. RM1008E, page 05-195).

      Result
      Result Proceed to
      DTC (C1251/51) is not output A
      DTC (C1251/51) is output B

      Tech Tips


      • If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU, with the ignition switch ON and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.

      • If the normal system code is output (the trouble code is not output), slightly jiggle the connectors, wire harness, and fuses of the skid control ECU and brake actuator assembly. Make sure that no DTCs are output.

      • If any DTCs are output while jiggling a connector or wire harness of the skid control ECU and brake actuator assembly, inspect and repair the connector or wire harness.

      • It is suspected that the DTCs were output due to a bad connection of the connector terminal.


    B

    REPLACE SKID CONTROL ECU

    A

    CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) Click here