CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0100

DTC Code DTC Name
U0100 Lost Communication with ECM / PCM "A"

DESCRIPTION

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

  • ECM main wire or connector

  • Power source circuit of ECM

  • ECM

WIRING DIAGRAM

A005L4JE03
A005KPBE02

CAUTION / NOTICE / HINT

Note


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

  • Turn the ignition switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.

  • Turn the ignition switch off before inspecting CAN bus wires for a ground short.

  • After the ignition switch is turned off, check that the key 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 ignition 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 ignition 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. CHECK FOR CAN BUS WIRE (ECM MAIN WIRE)


    1. Turn the ignition switch off.

    2. A005IRCE01
      A005GYLE01

      Disconnect the A58*1 or A59*2 ECM connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition

      A58-12 (CANP) - A58-25 (CANN)*1

      A59-17 (CANP) - A59-16 (CANN)*2

      		 Ignition switch off 108 to 132 Ω

      *1 : for 1NR-FE

      *2 : for 1ND-TV

      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM (for 1NR-FE))
      *b

      Front view of wire harness connector

      (to ECM (for 1ND-TV))

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Check for the ECM power source circuit (for 1ND-TV) Click here.

    2. Check for the ECM power source circuit (for 1NR-FE) Click here.

      Result
      Result Proceed to
      OK (for 1ND-TV) A
      OK (for 1NR-FE) B
      NG C

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)