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 motor relay supplies power to the pump motor. While the ABS is activated, the ECU turns the motor relay on and operates the 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. Detection Item DTC Detection Condition Trouble Area
C146C Open in ABS Motor Relay Circuit

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 17.4 V.

    • While initial check and ABS 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 9.5 V or higher.

    • Relay contact remains open when the relay is ON.

  • ABS NO. 1 fuse

  • Motor relay circuit

  • Brake actuator assembly (Motor relay)
C146D Short in ABS Motor Relay Circuit When the motor relay is OFF, the motor relay remains closed for 4 seconds or more.

  • Motor relay circuit

  • Brake actuator assembly (Motor relay)

WIRING DIAGRAM

B003QJFE03

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform Test Mode (Signal Check) to acquire the rear differential lock identification information.

    Click here

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

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 GTS (MOTOR RELAY)


    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Turn the GTS on.

    4. Enter the following menus: Chassis / ABS/VSC/TRC / Active Test.

    5. According to the display on the GTS, perform the Active Test.


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Motor Relay Motor relay Relay ON / OFF

      Operating sound of motor can be heard.

      Vehicle condition: Vehicle stopped

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      Motor Relay

    6. Check the operating sound of the motor relay when operating it with the GTS.

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

    The operating sound is heard

    GO TO STEP 4 Click here

    The operating sound is not heard

  2. CHECK TERMINAL VOLTAGE (+BM 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. Disconnect the A68 skid control ECU (brake actuator assembly) connector.

    4. B003Q7QC49
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A68-24 (+BM) - Body ground Always 11 to 14 V

    5. Turn the ignition switch off.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BM CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (GND2 TERMINAL)


    1. B003Q7QC48
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A68-13 (GND2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND2 CIRCUIT)

    OK

  4. RECONFIRM DTC

    Tech Tips

    These codes are detected when a problem is determined in the skid control ECU (brake actuator assembly).

    The motor circuit (motor relay circuit) are in the skid control ECU (brake actuator assembly).

    Therefore, motor circuit (motor relay circuit) inspection cannot be performed. Be sure to check if any DTCs are output before replacing the skid control ECU (brake actuator assembly).


    1. Reconnect the A68 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Turn the ignition switch off.

    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.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Proceed to
      DTC is not output
      DTC is output

      Tech Tips


      • If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU (brake actuator assembly), with the ignition switch to 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 (brake actuator assembly). Make sure that no DTCs are output.

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

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


    DTC is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC is output

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here