ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C146C and 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.

  3. 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

C284381E01

CAUTION / NOTICE / HINT

Note:

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

  • When replacing the skid control ECU (brake actuator assembly), perform acceleration sensor zero point calibration and CVT oil pressure calibration (for continuously variable transaxle).

    K111:Click here

    K111F:Click here

Tip:

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

    RECONFIRM DTCClick 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. Check the connector case and terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

    4. Disconnect the A63 skid control ECU (brake actuator assembly) connector.

    5. C199357C62

      *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

      A63-24 (+BM) - Body ground

      Always

      11 to 14 V

    6. 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. Turn the ignition switch off.

    2. C199357C63

      *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

      A63-13 (GND2) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  4. RECONFIRM DTC

    Tip:

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

    The solenoid circuits are in the skid control ECU (brake actuator assembly).

    Therefore, solenoid circuit inspection and solenoid unit 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 A63 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    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

      Chassis > ABS/VSC/TRC > Trouble Codes

      Result

      Proceed to

      DTC is not output

      DTC is output
      Tip:

      • 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 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 hereClick hereClick hereClick here

    DTC is output

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here