CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0104

DTC Code DTC Name
U0104 Lost Communication with Driving Support ECU

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
U0104 No communication from the driving support ECU assembly continues.

  • Driving support ECU assembly branch line or connector

  • Power source circuit of driving support ECU assembly

  • Driving support ECU assembly

Tech Tips

This diagnosis procedure is for when DTC U0104 is output by the power management control ECU (Intelligent tester display: PM1 Gateway).

WIRING DIAGRAM

A003Z2FE05

INSPECTION PROCEDURE

Note


  • Turn the power switch off before measuring the resistances between CAN main bus lines and between CAN branch lines.

  • Turn the power switch off before inspecting CAN bus lines for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. RECONFIRM DTC OUTPUT


    1. Reconfirm DTCs.

      Tech Tips

      If DTC U1002 is output from PM1 Gateway of the power management control ECU, this indicates a V2 bus malfunction. Troubleshoot for DTC U1002 and check for malfunctions in the V2 bus.

      Result
      Result Proceed to
      U1002 is not output from power management control ECU (Intelligent tester display/PM1 Gateway) A
      U1002 is output from power management control ECU (Intelligent tester display/PM1 Gateway) B

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK CAN BUS LINE FOR DISCONNECTION (DRIVING SUPPORT ECU ASSEMBLY BRANCH LINE)


    1. Turn the power switch off.

    2. A003VNUE60
      Text in Illustration
      *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 Switch Condition Specified Condition
      H5-39 (CA2H) - H5-17 (CA2L) Power switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. A003VNUE61
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      H5-30 (B) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  4. CHECK HARNESS AND CONNECTOR (GROUND TERMINAL)


    1. A003VNUE62
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H5-25 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here