CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0129

DTC Code DTC Name
U0129 Lost Communication with Skid Control ECU

DESCRIPTION

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from
U0129 Lost Communication with Skid Control ECU Communication stop occurs between the skid control ECU assembly and ECU or sensor outputs DTC(s)

  • Skid control ECU assembly

  • Driving support ECU assembly

  • Skid control ECU assembly CAN branch wire or connector

  • Driving support ECU assembly CAN branch wire or connector

  • Front steering control ECU (w/ Variable Gear Ratio Steering System)

  • Rack and pinion power steering gear assembly

  • Driving support ECU assembly

  • Rear steering control ECU (w/ Dynamic Rear Steering System)

WIRING DIAGRAM

B000VVKE01
*a Skid Control ECU Assembly
*b Driving Support ECU Assembly
*c No. 8 CAN Junction Connector

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note


  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

    Click here

  • Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

  • Some parts must be initialized and set when replacing or removing and installing parts.

    Click here

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

    Click here

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK FOR DTCs


    1. Check for DTCs.

      Result
      Result Proceed to
      DTC U0129 is output from driving support ECU assembly only. A
      DTC U0129 is output from any ECU. B

    B

    CHECK FOR OPEN IN CAN BUS WIRE (SKID CONTROL ECU ASSEMBLY BRANCH WIRE) Click here

    A

  2. CHECK FOR OPEN IN CAN BUS WIRE (DRIVING SUPPORT ECU ASSEMBLY BRANCH WIRE)


    1. Disconnect the cable from the negative (-) battery terminal.

    2. B000Y7JC06
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the driving support ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P62-12 (CA3H) - P62-13 (CA3L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR

  3. CHECK FOR OPEN IN CAN BUS WIRE (SKID CONTROL ECU ASSEMBLY BRANCH WIRE)


    1. Disconnect the cable from the negative (-) battery terminal.

    2. B000XESC01
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

      Disconnect the skid control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A9-10 (CA2H) - A9-11 (CA2L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE SKID CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE SKID CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR