CAN COMMUNICATION SYSTEM(for LHD), Diagnostic DTC:U0122, U0129

DTC Code DTC Name
U0122 Lost Communication with Vehicle Dynamics Control Module
U0129 Lost Communication with Brake System Control Module

DESCRIPTION

DTC Code DTC Detection Condition Trouble Area
U0122 There is no communication from the skid control ECU assembly.

  • Power source or inside of skid control ECU assembly

  • Skid control ECU assembly CAN branch wire or connector

  • Skid control ECU assembly
U0129 There is no communication from the skid control ECU assembly.

  • Power source or inside of skid control ECU assembly

  • Skid control ECU assembly CAN branch wire or connector

  • Skid control ECU assembly

WIRING DIAGRAM

A001CFXE01

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE


  1. PRECAUTION

    Note

    After turning the engine switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work Click here.


    NEXT

  2. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL


    1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the CAN main wire and the CAN branch wire.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.


    NEXT

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


    1. A001B8VE03
      Text in Illustration
      *A Steering Bus
      *B Braking and Driving Bus
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

      Disconnect the skid control ECU assembly connectors.

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

      Standard Resistance
      Steering Bus
      Tester Connection Switch Condition Specified Condition
      A21-30 (CA1H) - A21-29 (CA1L) Engine switch off 54 to 69 Ω
      Braking and Driving Bus
      Tester Connection Switch Condition Specified Condition
      A19-7 (CA2H) - A19-6 (CA2L) Engine switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE SKID CONTROL ECU ASSEMBLY CAN BRANCH WIRE OR CONNECTOR (CA1H, CA1L, CA2H, CA2L)

    OK

  4. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY - BATTERY AND BODY GROUND)


    1. A001AQJE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

      Connect the cable to the negative (-) battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A19-43 (+BI1) - Body ground Always 11 to 14 V
      A21-38 (+BI2) - Body ground Always 11 to 14 V
      A19-29 (+BI3) - Body ground Always 11 to 14 V
      A21-22 (+BI4) - Body ground Always 11 to 14 V
      A19-46 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      A21-46 (IG2) - Body ground Engine 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
      A19-1 (GND) - Body ground Always Below 1 Ω
      A21-1 (GND4) - Body ground Always Below 1 Ω

    OK

    REPLACE SKID CONTROL ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR