CAN COMMUNICATION SYSTEM ECM Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
ECM Communication Stop Mode

  • "Engine" and "ECT" are not displayed on "Communication Bus Check" screen of the intelligent tester.

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

  • Power source circuit of the ECM

  • ECM main wire or connector

  • ECM

WIRING DIAGRAM

A01CAVZE01
A01CBKUE01

INSPECTION PROCEDURE

Note


  • Turn the engine switch off before measuring the resistances of the CAN main wires and the CAN branch wires.

  • After the engine switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.

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

Tech Tips


  • Operating the engine 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 will help determine the cause of the malfunction.

PROCEDURE


  1. CHECK CAN BUS WIRE FOR DISCONNECTION (ECM MAIN WIRE)


    1. A01CD8TE06

      Turn the engine switch off.

    2. 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
      A8-41 (CANH) - A8-49 (CANL) Engine switch off 108 to 132 Ω

    NG

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

    OK

  2. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit.

      Tech Tips


      Result
      Result Proceed to
      OK (for 2AZ-FE) A
      OK (for 2GR -FE) B
      NG C

    B

    REPLACE ECM (for 2GR-FE) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    A

    REPLACE ECM (for 2AZ-FE) Click here