ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1377/43

DTC Code DTC Name
C1377/43 Capacitor Malfunction

DESCRIPTION

The brake control power supply assembly is used as auxiliary power for brake control when the auxiliary battery voltage is low.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1377/43 Capacitor Malfunction

101

102

103

105

106

108

109

110

  • INF Code: 101


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Brake control power supply assembly is deteriorated (replacement necessary).

  • INF Code: 102


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Self discharge (current leak) is excessive (internal malfunction).

  • INF Code: 103


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Overvoltage (16.4 V or more) continues to be applied from the auxiliary battery to the brake control power supply assembly voltage input (+BC) for 10 seconds or more.

  • INF Code: 105


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Circuit inside the power back up unit (charge) is malfunctioning.

  • INF Code: 106


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Circuit inside the power back up unit (back up output circuit) is malfunctioning.

  • INF Code: 108


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Circuit inside the power back up unit (voltage monitor circuit) is malfunctioning.

  • INF Code: 109


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Open circuit between auxiliary battery (12 V) and brake control power supply assembly power input (+BC terminal).

  • INF Code: 110


    • Either of the following is detected:


      1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not brake control power supply assembly communication malfunction) reception condition continues for 3 seconds or more.

      2. Open or short circuit between auxiliary battery (12 V) and brake control power supply assembly output 1 (OUT1).

      3. Open or short circuit between auxiliary battery (12 V) and brake control power supply assembly output 2 (OUT2).

  • INF Code: 101, 102, 105, 106, 108


    • Brake control power supply assembly

  • INF Code: 103


    • Apply high voltage

  • INF Code: 109


    • CAPACITOR fuse

    • Wire harness and connector

    • Improperly connected connector, deformation or corrosion of terminals

  • INF Code: 110


    • Wire harness and connector

    • Improperly connected connector, deformation or corrosion of terminals

 Electronically controlled brake system DTC

WIRING DIAGRAM

A0021S8E03

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU assembly, perform initialization and calibration of the linear solenoid valve.

    Click here

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

PROCEDURE


  1. CHECK FREEZE FRAME DATA


    1. Check the INF code from the Freeze Frame Data memorized when the DTC (C1377/43) is stored.

      Click here

      Result
      Result Proceed to
      INF codes 109 and/or 110 are output. A
      INF codes 101, 102, 105, 106 and/or 108 are output. B
      INF code 103 is output. C

    B

    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY for LHD: Click here
    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY for RHD: Click here

    C

    CHECK AUXILIARY BATTERY Click here

    A

  2. CHECK HARNESS AND CONNECTOR (+BC TERMINAL)


    1. A002343C08
      *a

      Front view of wire harness connector

      (to Brake Control Power Supply Assembly)

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

    2. Disconnect the K40 brake control power supply assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      K40-5 (+BC) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. A002343C09
      *a

      Front view of wire harness connector

      (to Brake Control Power Supply Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K40-8 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  4. INSPECT BRAKE CONTROL POWER SUPPLY ASSEMBLY (BRAKE CONTROL POWER SUPPLY ASSEMBLY POWER SUPPLY OUTPUT)


    1. A0020JIC03
      *a

      Component with harness connected

      (Brake Control Power Supply Assembly)

      Reconnect the K40 brake control power supply assembly connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 (OUT1) - Body ground Power switch on (IG) 11 to 14 V
      4 (OUT2) - Body ground Power switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY for LHD: Click here
    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY for RHD: Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY - BRAKE CONTROL POWER SUPPLY ASSEMBLY)


    1. Turn the power switch off.

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

    3. Disconnect the A24 and A25 skid control ECU assembly connectors.

    4. Disconnect the K40 brake control power supply assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A24-38 (CBI1) - K40-1 (OUT1) Always Below 1 Ω
      A24-38 (CBI1) or K40-1 (OUT1) - Body ground Always 10 kΩ or higher
      A25-40 (CBI2) - K40-4 (OUT2) Always Below 1 Ω
      A25-40 (CBI2) or K40-4 (OUT2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. RECONFIRM DTC


    1. Reconnect the A24 and A25 skid control ECU assembly connectors.

    2. Reconnect the K40 brake control power supply assembly connector.

    3. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    4. Turn the power switch off.

    5. Turn the power switch on (IG).

    6. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C1377/43 is not output A
      DTC C1377/43 is output B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE SKID CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE SKID CONTROL ECU ASSEMBLY for RHD: Click here

  7. CHECK AUXILIARY BATTERY


    1. Check the auxiliary battery voltage.

      Standard Voltage
      Tester Connection Condition Specified Condition
      Auxiliary battery Power switch on (IG) 11 to 14 V
      Auxiliary battery Power switch on (READY) 11 to 15.5 V
      Result
      Proceed to
      OK
      NG

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  8. CHECK HARNESS AND CONNECTOR (+BC TERMINAL)


    1. A002343C08
      *a

      Front view of wire harness connector

      (to Brake Control Power Supply Assembly)

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

    2. Disconnect the K40 brake control power supply assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      K40-5 (+BC) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  9. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. A002343C09
      *a

      Front view of wire harness connector

      (to Brake Control Power Supply Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K40-8 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY for LHD: Click here
    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)