CAN COMMUNICATION SYSTEM(for LHD with Entry and Start System), Diagnostic DTC:U0104

DTC Code DTC Name
U0104 Lost Communication with Driving Support ECU

DESCRIPTION

DTC Code DTC Detection Condition Trouble Area
U0104 There is no communication from the driving support ECU.

  • Power source or inside driving support ECU assembly

  • Driving support ECU assembly CAN branch wire or connector

  • Driving support ECU assembly

WIRING DIAGRAM

A01XM41E61
*a No. 1 Junction Connector
*b ECU-IG NO. 1
*c from IG1 NO.1 Relay
*d Driving Support ECU Assembly

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. 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 CAN branch wire.

      CAUTION:

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

      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.

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


    NEXT

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


    1. A01XJ9NE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the G119 driving support ECU assembly connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      G119-39 (CA2H) - G119-17 (CA2L) Engine switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE DRIVING SUPPORT ECU ASSEMBLY CAN BRANCH WIRE OR CONNECTOR (CA2H, CA2L)

    OK

  3. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - BATTERY AND BODY GROUND)


    1. A01XEMSE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Driving Support 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 resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      G119-25 (GND) - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G119-30 (B) - Body ground Engine switch on (IG) 11 to 14 V

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR