ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1377/43

DTC Code DTC Name
C1377/43 Capacitor Malfunction

DESCRIPTION

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

DTC Code INF Code DTC Detection Condition Trouble Area
C1377/43 101

Either of the following is detected:


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

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

 Brake control power supply assembly
↑ 102

Either of the following is detected:


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

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

 ↑
↑ 103

Either of the following is detected:


  1. IG1 terminal voltage is 9.5 V or more, and malfunction signal (not capacitor 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 capacitor voltage input (+BC) for 10 seconds or more.

 Apply high voltage
↑ 105

Either of the following is detected:


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

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

 Brake control power supply assembly
↑ 106

Either of the following is detected:


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

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

 ↑
↑ 108

Either of the following is detected:


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

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

 ↑
↑ 109

Either of the following is detected:


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

  2. Open circuit between auxiliary battery (12 V) and capacitor power input (+BC terminal).

  • CAPACITOR (HV) fuse

  • Brake control power supply circuit
↑ 110

Either of the following is detected:


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

  2. Open or short circuit between auxiliary battery (12 V) and capacitor output 1 (OUT1).

  3. Open or short circuit between auxiliary battery (12 V) and capacitor output 2 (OUT2).

 Brake control power supply circuit

WIRING DIAGRAM

A01FRLPE03

INSPECTION PROCEDURE

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 inspection 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 Click here

    C

    CHECK AUXILIARY BATTERY Click here

    A

  2. CHECK HARNESS AND CONNECTOR (+BC TERMINAL)


    1. A01FUJCE04
      Text in Illustration
      *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 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
      X7-5 (+BC) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  3. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. A01FUJCE05
      Text in Illustration
      *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
      X7-8 (GND) - Body ground Always Below 1 Ω

    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. A01FQRJE02
      Text in Illustration
      *a

      Component with harness connected

      (Brake Control Power Supply Assembly)

      Reconnect the 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 Switch Condition Specified Condition
      X7-1 (OUT1) - Body ground Power switch on (IG) 11 to 14 V
      X7-4 (OUT2) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY Click here

    OK

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


    1. Turn the power switch on (IG).

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

    3. Disconnect the A14 and A16 skid control ECU assembly connectors and the X7 brake control power supply assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A14-38 (CBI1) - X7-1 (OUT1) Always Below 1 Ω
      A14-38 (CBI1) - Body ground Always 10 kΩ or higher
      A16-40 (CBI2) - X7-4 (OUT2) Always Below 1 Ω
      A16-40 (CBI2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. RECONFIRM DTC


    1. Reconnect the skid control ECU assembly connectors and the brake control power supply assembly connector.

    2. Clear the DTCs Click here.

    3. Turn the power switch on (IG).

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

      Result
      Result Proceed to
      DTC (C1377/43) is not output A
      DTC (C1377/43) is output B

    B

    REPLACE SKID CONTROL ECU ASSEMBLY Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  7. CHECK AUXILIARY BATTERY


    1. Check the auxiliary battery voltage.

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

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  8. CHECK HARNESS AND CONNECTOR (+BC TERMINAL)


    1. A01FUJCE04
      Text in Illustration
      *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 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
      X7-5 (+BC) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  9. CHECK HARNESS AND CONNECTOR (GND TERMINAL)


    1. A01FUJCE05
      Text in Illustration
      *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
      X7-8 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY Click here