CAN COMMUNICATION SYSTEM(for RHD) ECM Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
ECM Communication Stop Mode

Either condition is met:


  • "ECM (Engine)" is not displayed on "CAN Bus Check".

    Click here

  • Communication system DTCs (DTCs that start with U) that are output correspond to "ECM Communication Stop Mode" in "DTC Combination Table".

    Click here


  • Power source circuit of ECM

  • ECM ground circuit

  • ECM CAN main wire or connector

  • ECM

WIRING DIAGRAM

B003O2QE05

CAUTION / NOTICE / HINT

Note


  • 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

  • Before measuring the resistance of the CAN bus, turn the ignition 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 (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work.

    Click here

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

  • DTC check procedure: Turn the ignition switch ON, wait at least 20 seconds, and then drive the vehicle at a speed of 15 km/h (9 mph) or more for 3 seconds or more.

  • 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 ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • 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 WIRE (ECM CAN MAIN WIRE)


    1. B003M4YC04
      *a

      Front view of wire harness connector

      (to ECM)

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

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G49-17 (CANH) - G49-28 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE ECM CAN MAIN WIRE OR CONNECTOR (CANH, CANL)

    OK

  2. CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND)


    1. Connect the cable to the negative (-) battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

      Click here

      B003KONC02
      *a

      Front view of wire harness connector

      (to ECM)

      		 - -

    2. Disconnect the ECM connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G50-1 (BATT) - Body ground Always 11 to 14 V
      G50-2 (+B) - Body ground Battery positive (+) voltage applied to terminal G49-14 (MREL) 11 to 14 V
      G50-3 (+B2) - Body ground Battery positive (+) voltage applied to terminal G49-14 (MREL) 11 to 14 V
      G50-4 (+B3) - Body ground Battery positive (+) voltage applied to terminal G49-14 (MREL) 11 to 14 V
      G50-18 (IGSW) - Body ground Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C41-1 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR