CAN COMMUNICATION SYSTEM ECM Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
ECM Communication Stop Mode

  • "ECM (Engine)" and/or "TCM" are not displayed on the "CAN Bus Check" screen of the GTS.

  • Applies to ECM Communication Stop Mode in DTC Combination Table.

  • Power source circuit of ECM

  • ECM main wire or connector

  • ECM

WIRING DIAGRAM

A01EM5RE09

INSPECTION PROCEDURE

Note


  • 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 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 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 OPEN IN CAN BUS WIRES (ECM MAIN WIRE)


    1. Turn the ignition switch off.

    2. A01EMIIE21
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the connector of the ECM.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A49-13 (CANH) - A49-5 (CANL) Ignition switch off 108 to 132 Ω

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. Check the ECM Power Source Circuit Click here.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

    REPLACE ECM Click here