ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C146C, C146D

DTC Code DTC Name
C146C Open in ABS Motor Relay Circuit
C146D Short in ABS Motor Relay Circuit

DESCRIPTION

The ABS motor relay supplies power to the ABS pump motor. While the ABS is activated, the ECU turns the motor relay on and operates the ABS pump motor.

If the voltage supplied to the motor relay (BM) is below the DTC's detection threshold due to low voltage from the battery or generator, the DTC may be stored.

DTC NO. DTC Detection Condition Trouble Area
C146C

When either of the following is detected:


  1. All of the following conditions continue for 0.12 seconds or more.


    • The IG1 terminal voltage is between 9.5 and 17.2 V.

    • While initial check and ABS, BA, TRC or VSC is operating.

    • Relay contact is open when the relay is ON.

  2. Both of the following conditions continue for 0.12 seconds.


    • The IG1 terminal voltage is less than 9.5 V.

    • Relay contact remains open when the relay is ON.

  • ABS NO. 1 fuse

  • ABS motor relay circuit

  • Brake actuator assembly (Skid control ECU) (ABS motor relay)
C146D When the motor relay is OFF, the motor relay remains closed for 4 seconds or more.

  • ABS motor relay circuit

  • Brake actuator assembly (Skid control ECU) (ABS motor relay)

WIRING DIAGRAM

Refer to DTCs C1427 Click here.

CAUTION / NOTICE / HINT

Note


  • When replacing the brake actuator assembly (skid control ECU) or deceleration sensor, be sure to perform deceleration sensor 0 point calibration and CVT oil pressure calibration after performing AT/CVT learned values initialization.

    for K310 Click here

    for K411 Click here

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

  • Perform the test mode procedure after the initialization (perform the test mode start only after the brake actuator assembly (skid control ECU) is replaced).

    Tech Tips

    By performing the test mode start, the identification code of the brake actuator assembly (skid control ECU) is re-registered.

Tech Tips

When C1241 is output together with C146C and/or C146D inspect and repair the trouble areas indicated by C1241 first Click here.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

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

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

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

      Result
      Result Proceed to
      The operating sound is not heard A
      The operating sound is heard B

    B

    RECONFIRM DTC Click here

    A

  2. CHECK TERMINAL VOLTAGE (BM)


    1. Turn the ignition switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

    3. Check the connector case and terminals for deformation and corrosion.

      Standard condition
      No deformation or corrosion.
    4. A005MIBE01
      Text in Illustration
      *A except LHD with CVT
      *B for LHD with CVT
      *a

      Front view of wire harness connector

      (to brake actuator assembly (skid control ECU))

      Disconnect the A55 or A57 brake actuator assembly (skid control ECU) connector.

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

      Standard Voltage
      except LHD with CVT
      Tester Connection Condition Specified Condition
      A55-24 (+BM) - Body ground Always 11 to 14 V
      for LHD with CVT
      Tester Connection Condition Specified Condition
      A57-24 (+BM) - Body ground Always 11 to 14 V

    6. Reconnect the A55 or A57 brake actuator assembly (skid control ECU) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BM CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (GND2 TERMINAL)


    1. Turn the ignition switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

    3. A005LOKE01
      Text in Illustration
      *A except LHD with CVT
      *B for LHD with CVT
      *a

      Front view of wire harness connector

      (to brake actuator assembly (skid control ECU))

      Disconnect the A55 or A57 brake actuator assembly (skid control ECU) connector.

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

      Standard Resistance
      except LHD with CVT
      Tester Connection Condition Specified Condition
      A55-13 (GND2) - Body ground Always Below 1 Ω
      for LHD with CVT
      Tester Connection Condition Specified Condition
      A57-13 (GND2) - Body ground Always Below 1 Ω

    5. Reconnect the A55 or A57 brake actuator assembly (skid control ECU) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  4. RECONFIRM DTC

    Tech Tips

    This code is detected when a problem is identified in the brake actuator assembly.

    The ABS motor relay is in the brake actuator assembly.

    Therefore, ABS motor relay unit inspection cannot be performed. Be sure to check if the DTC is output before replacing the brake actuator assembly.


    1. Turn the ignition switch off.

    2. Clear the DTCs Click here.

    3. Start the engine.

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

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

      Result
      Result Proceed to
      DTC (C1427) is not output A
      DTC (C1427) is output (for LHD) B
      DTC (C1427) is output (for RHD) C

      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 (no trouble codes are output), slightly jiggle the connectors, wire harness, and fuses of the brake actuator assembly. Make sure that no DTCs are output.

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

      • The DTCs were probably output due to a bad connection of the connector terminal.


    A

    CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) Click here

    C

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) Click here