ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1437

DTC Code DTC Name
C1437 Lost Communication with ECM

DESCRIPTION

The skid control ECU (brake actuator assembly) receives signals from the ECM via CAN communication.

DTC No. Detection Item DTC Detection Condition Trouble Area Note
C1437 Lost Communication with ECM When the +BS terminal voltage is between 10 to 17.4 V and the vehicle speed is 15 km/h (9 mph) or more, data cannot be sent to the ECM for 2 seconds or more.

  • CAN communication system

  • Skid control ECU (brake actuator assembly)

  • ECM

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CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information.

Click here

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)


    1. Using the GTS, check for any momentary interruption in the wire harness and connector corresponding to a DTC.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      EFI Communication Open ECM communication open detection Error or Normal

      Error: Momentary interruption detected

      Normal: Momentary interruption not detected

      		 After a momentary interruption occurs, if there is no momentary interruption for 1 second, it switches from "Error" to "Normal".
      EFI Communication Invalid ECM communication invalid detection Error or Normal

      Error: ECM communication invalid state detected

      Normal: ECM communication invalid state not detected

      		 After ECM communication invalid state occurs, if there no further invalid state occurs, it switches from "Error" to "Normal".

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      EFI Communication Open
      EFI Communication Invalid
      OK
      Normal (There are no momentary interruptions.)

      Tech Tips

      Perform the above inspection before removing the connector.

      Result
      Proceed to
      OK
      NG

    NG

    CHECK CAN COMMUNICATION SYSTEM Click here

    OK

  2. RECONFIRM DTC


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the engine switch off.

    3. Start the engine.

    4. Perform a road test.

    5. Check that no CAN communication system DTCs are output.

      Click here

    6. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C1437 is not output. A
      DTC C1437 is output. B
      CAN communication system DTCs are output. C

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY for LHD: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY for RHD: Click here

    C

    INSPECT CAN COMMUNICATION SYSTEM Click here