ECD SYSTEM, Diagnostic DTC:U0129

DTC Code DTC Name
U0129 Lost Communication with Brake System Control Module

DESCRIPTION

The ECM and skid control ECU (brake actuator assembly) communicate with each other via the CAN communication line

If there is a problem in this communication, the ECM stores the DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
U0129 Lost Communication with Brake System Control Module

No communication between ECM and skid control ECU.

(1 trip detection logic)

  • Wire harness (CANL and CANH circuits)

  • ECM

  • Skid control ECU (brake actuator assembly)

 Comes on DTC stored

WIRING DIAGRAM

A01QOCCE05
*1 Skid Control ECU (Brake Actuator Assembly)

CAUTION / NOTICE / HINT

Note

When replacing the ECM, the ECM needs registration and initialization.

Tech Tips


  • When a DTC indicating a CAN communication system malfunction is output, repair the CAN communication system before repairing each corresponding sensor.

  • Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

  • If the CAN communication malfunctions, there is no data output from the ECM. In this case, some of the freeze frame data is not correct and not identical to the ECM data. However the ECM data is correct.

  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing the new ECM, perform all of the initialization/registrations for the "Learning Values Write" function by following the instructions shown on the GTS display.

PROCEDURE


  1. GO TO CAN COMMUNICATION SYSTEM


    1. Go to CAN communication system for troubleshooting.


      • CAN malfunction system (for LHD with Centrol Gateway ECU)

        Click here

      • CAN malfunction system (for RHD with Centrol Gateway ECU)

        Click here

      • CAN malfunction system (for LHD without Centrol Gateway ECU)

        Click here

      • CAN malfunction system (for RHD without Centrol Gateway ECU)

        Click here

      Result
      Proceed to
      NEXT

    NEXT

    END