CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU), 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 ground circuit

  • ECM

Tech Tips

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

WIRING DIAGRAM

A005AAZE08

CAUTION / NOTICE / HINT

Note


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

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

  • 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.

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

  • DTC check procedure: Turn the power switch on (IG) and wait at least 20 seconds.

  • After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.

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 sub bus 12 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in sub bus 12.

      Result
      Result Proceed to
      U1002 is not output from power management control ECU (GTS display: PM2 Gateway) A
      U1002 is output from power management control ECU (GTS display: PM2 Gateway) B

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK FOR OPEN IN CAN BUS LINES (ECM - SUB BUS 12)


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

    2. A005DWYE02
      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 Condition Specified Condition
      A57-12 (CANP) - A57-4 (CANN) Cable disconnected from negative (-) auxiliary battery terminal 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 Click here.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)