CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0100

DTC Code DTC Name
U0100 Lost Communication with ECM / PCM

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
U0100 No communication from the ECM continues.

  • ECM main line or connector

  • Power source circuit of ECM

  • ECM

Tech Tips

This diagnosis procedure is for when DTC U0100 is output by the power management control ECU (Intelligent tester display: PM2 Gateway).

WIRING DIAGRAM

A003YX3E01

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 PM2 Gateway of the power management control ECU, this indicates a power management bus malfunction. Troubleshoot for DTC U1002 and check for malfunctions in the power management bus.

      Result
      Result Proceed to
      U1002 is not output from power management control ECU (Intelligent tester display/PM2 Gateway) A
      U1002 is output from power management control ECU (Intelligent tester display/PM2 Gateway) B

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK CAN BUS LINE FOR DISCONNECTION (ECM - POWER MANAGEMENT BUS)


    1. Turn the power switch off.

    2. A003W8AE57
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A60-12 (CANP) - A60-4 (CANN) Power switch off 108 to 132 Ω

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (ECM MAIN LINE)

    OK

  3. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit.


      Result
      Result Proceed to
      OK (for 2ZR-FXE) A
      OK (for 5ZR-FXE) B
      NG C

    B

    REPLACE ECM Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    A

    REPLACE ECM Click here