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 battery voltage is low.

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

When both conditions below are met:


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

  • Brake control power supply is deteriorated (indicates a need to replace).

 Brake control power supply
↑ 102

When both conditions below are met:


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

  • Self-discharge (current leak) is excessive (internal malfunction).

 ↑
↑ 103

When both conditions below are met:


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

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

 Positive battery circuit (Apply high voltage)
↑ 105

When both conditions below are met:


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

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

 Brake control power supply
↑ 106

When both conditions below are met:


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

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

 ↑
↑ 108

When both conditions below are met:


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

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

 ↑
↑ 109

When both conditions below are met:


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

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

  • ABS MAIN4 fuse

  • Wire harness or connector
↑ 110

When both conditions below are met:


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

  2. When either of the following is detected:


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

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

  • ABS MAIN4 fuse

  • Wire harness or connector

WIRING DIAGRAM

A01GMTEE04

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK FREEZE FRAME DATA


    1. Check the information code from the "FREEZE FRAME DATA" memorized when the DTC (C1377/43) is stored Click here.

      Result
      Result Proceed to
      Information codes (109 and 110) are output A
      Information codes (101, 102, 105, 106 and 108) are output B
      Information code (103) is output C

    B

    REPLACE BRAKE CONTROL POWER SUPPLY Click here

    C

    INSPECT BATTERY Click here

    A

  2. INSPECT FUSE (ABS MAIN4)


    1. Remove the ABS MAIN4 fuse from the luggage room junction block.

    2. Measure the resistance of the fuse.

      Standard resistance
      Tester Connection Condition Specified Condition
      ABS MAIN4 fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

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


    1. A01GKMFE13

      Disconnect the S49 power supply connector.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      S49-8 (+BC) - Body ground Always 11 to 14 V

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

      Standard resistance
      Tester Connection Condition Specified Condition
      S49-14 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC OR GND CIRCUIT)

    OK

  4. INSPECT BRAKE CONTROL POWER SUPPLY (OUT1 AND OUT2 TERMINAL)


    1. A01GKMFE14

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

      Tech Tips

      Perform inspection while the brake is not operated.

      Standard voltage
      Tester Connection Condition Specified Condition
      S49-1 (OUT1) - Body ground While the brake is not operated 11 to 14 V
      S49-7 (OUT2) - Body ground While the brake is not operated 11 to 14 V

    OK

    RECONFIRM DTC Click here

    NG

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


    1. Disconnect the A19 and A21 ECU connectors.

    2. Disconnect the S49 power supply connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A19-38 (CBI1) - S49-1 (OUT1) Always Below 1 Ω
      A21-40 (CBI2) - S49-7 (OUT2) Always Below 1 Ω
      A19-38 (CBI1) - Body ground Always 10 kΩ or higher
      A21-40 (CBI2) - Body ground Always 10 kΩ or higher

    OK

    RECONFIRM DTC Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. INSPECT BATTERY


    1. Check the battery voltage.

      Result
      Result Proceed to

      OK

      (Standard voltage: 11 to 14 V)

      		 A

      for 1UR-FSE:

      NG

      		 B

      for 1UR-FE:

      NG

      		 C

    B

    INSPECT CHARGING SYSTEM (for 1UR-FSE) Click here

    C

    INSPECT CHARGING SYSTEM (for 1UR-FE) Click here

    A

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


    1. A01GKMFE15

      Disconnect the S49 power supply connector.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      S49-8 (+BC) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)

    OK

  8. RECONFIRM DTC


    1. Clear the DTC Click here.

    2. Turn the engine switch on (IG).

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

      Tech Tips

      Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

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

    B

    REPLACE BRAKE CONTROL POWER SUPPLY Click here

    A

    END