ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1377/43

DTC Code DTC Name
C1377/43 Capacitor Malfunction

DESCRIPTION

The brake control power supply (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 is deteriorated (replacement necessary).

 Brake control power supply
↑ 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
↑ 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 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

A01NDQ1E02

INSPECTION PROCEDURE

Note

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

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 Click here

    C

    CHECK AUXILIARY BATTERY Click here

    A

  2. INSPECT CAPACITOR FUSE


    1. A01NHC2E01
      Text in Illustration
      *1 Fuse Box
      *2 CAPACITOR Fuse

      Remove the CAPACITOR fuse from the fuse box.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      CAPACITOR (10 A) fuse Always Below 1 Ω

    NG

    REPLACE CAPACITOR FUSE

    OK

  3. INSPECT BRAKE CONTROL POWER SUPPLY (+BC TERMINAL)


    1. A01NGIYE09
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Brake Control Power Supply)

      Install the CAPACITOR fuse.

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

    3. Disconnect the brake control power supply connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      P47-8 (+BC) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  4. INSPECT BRAKE CONTROL POWER SUPPLY (GND TERMINAL)


    1. A01NGIYE10
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Brake Control Power Supply)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P47-14 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  5. INSPECT BRAKE CONTROL POWER SUPPLY (CAPACITOR POWER SUPPLY OUTPUT)


    1. A01NDF1E04
      Text in Illustration
      *1

      Component with harness connected

      (Brake Control Power Supply)

      Reconnect the brake control power supply 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
      P47-1 (OUT1) - Body ground Power switch on (IG) 11 to 14 V
      P47-7 (OUT2) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPLACE BRAKE CONTROL POWER SUPPLY Click here

    OK

  6. INSPECT SKID CONTROL ECU (CAPACITOR POWER SUPPLY INPUT)


    1. A01NDO9E31
      Text in Illustration
      *1

      Component with harness connected

      (Skid Control ECU)

      Reconnect the skid control ECU connectors.

    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
      A90-7 (CBI1) - Body ground Power switch on (IG) 8.8 to 14 V
      A91-2 (CBI2) - Body ground Power switch on (IG) 8.8 to 14 V

    NG

    REPLACE SKID CONTROL ECU Click here

    OK

  7. RECONFIRM DTC


    1. Turn the power switch off.

    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 Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  8. CHECK AUXILIARY BATTERY


    1. Check the auxiliary battery voltage.

      Standard Voltage
      11 to 14 V

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  9. INSPECT BRAKE CONTROL POWER SUPPLY (+BC TERMINAL)


    1. A01NGIYE09
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Brake Control Power Supply)

      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 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      P47-8 (+BC) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  10. INSPECT BRAKE CONTROL POWER SUPPLY (GND TERMINAL)


    1. A01NGIYE10
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Brake Control Power Supply)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P47-14 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

    REPLACE BRAKE CONTROL POWER SUPPLY Click here