CAN COMMUNICATION SYSTEM(for LHD) 4WD Control ECU Communication Stop Mode

DESCRIPTION

Detection Item Detection Item Trouble Area
4WD Control ECU Communication Stop Mode

Either condition is met:


  • "Four Wheel Drive Control" is not displayed on the "CAN Bus Check".

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  • Communication system DTCs (DTCs that start with U) that are output correspond to "4WD Control ECU Communication Stop Mode" in "DTC Combination Table".

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  • Power source circuit of 4WD ECU assembly

  • 4WD ECU assembly CAN branch wire or connector

  • 4WD ECU assembly

WIRING DIAGRAM

A01QQ9UE02
*a No. 2 CAN Junction Connector
*b ECU-IG NO.1
*c from IG1 NO.1 Relay
*d 4WD ECU Assembly

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.

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  • 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.

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

  • DTC check procedure: Drive the vehicles for 4.5 seconds or more at a speed 60 km/h (37 mph) 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.

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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 (4WD ECU ASSEMBLY CAN BRANCH WIRE)


    1. A01QTBYC03
      *a

      Rear view of wire harness connector

      (to 4WD ECU Assembly)

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

    2. Disconnect the 4WD ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G86-6 (CANH) - G86-5 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE 4WD ECU ASSEMBLY CAN BRANCH WIRE OR CONNECTOR (CANH, CANL)

    OK

  2. CHECK HARNESS AND CONNECTOR (4WD ECU ASSEMBLY - BATTERY AND BODY GROUND)


    1. A01QTBYC04
      *a

      Rear view of wire harness connector

      (to 4WD ECU Assembly)

      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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G86-3 (IG1) - Body ground Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G86-4 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE 4WD ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR