ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1378/44

DTC Code DTC Name
C1378/44 Capacitor Communication Malfunction

DESCRIPTION

Refer to DTC C1377/43 Click here.

DTC Code Information Code DTC Detection Condition Trouble Area
C1378/44 112

When one of the following is detected:


  1. Open or short in FAIL line.

  2. Malfunction inside the power back up unit.

  3. IG1 terminal voltage is 9.5 V or more, and condition that capacitor communication malfunction signal is received or capacitor communication is malfunctioning continues for 12 seconds or more.

  • Harness or connector

  • Brake control power supply

  • Skid control ECU

WIRING DIAGRAM

Refer to DTC C1377/43 Click here.

INSPECTION PROCEDURE

Note

When replacing the skid control ECU, perform the following operations:


  • Initialization of linear solenoid valve and calibration Click here

  • Yaw rate and acceleration sensor zero point calibration Click here

PROCEDURE


  1. CHECK TERMINAL VOLTAGE AND RESISTANCE (IG, GND)


    1. A01H240E10

      Disconnect the R72 power supply connector.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      R72-5 (IG1) - Body ground Power switch ON (IG) 11 to 14 V

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

      Standard resistance
      Tester Connection Condition Specified Condition
      R72-14 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the A19 and A21 ECU connectors.

    2. Disconnect the R72 power supply connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A19-8 (ENA) - R72-12 (ENA) Always Below 1 Ω
      A21-41 (FAIL) - R72-13 (FAIL) Always Below 1 Ω
      A19-8 (ENA) - Body ground Always 10 kΩ or higher
      A21-41 (FAIL) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. RECONFIRM DTC


    1. Clear the DTC Click here.

    2. Turn the power switch ON (IG).

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

      Tech Tips

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

      Result
      Result Proceed to
      DTC (C1378/44) is output A
      DTC (C1378/44) is not output B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  4. CHECK FREEZE FRAME DATA


    1. Check the information code from the "FREEZE FRAME DATA" memorized when the DTC (C1378/44) is stored Click here.

      Result
      Result Proceed to
      Information code (112) is output A
      Information code is not output for LHD B
      for RHD C

    B

    REPLACE SKID CONTROL ECU Click here

    C

    REPLACE SKID CONTROL ECU Click here

    A

    REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY Click here