CAN COMMUNICATION SYSTEM 4WD Control ECU Communication Stop Mode

DESCRIPTION

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

Any of the following conditions are met:


  • Communication stop for "Four Wheel Drive Control" is indicated on "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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  • 4WD ECU assembly CAN branch wire or connector

  • Power source circuit of 4WD ECU assembly

  • 4WD ECU assembly ground circuit

  • 4WD ECU assembly

WIRING DIAGRAM

B008GPTE11
*a No. 1 CAN Junction Connector
*b ECU-IG NO.6
*c from IG1 Relay
*d 4WD ECU Assembly

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note


  • Before measuring the resistance of the CAN bus, turn the engine 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 engine 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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  • Some parts must be initialized and set when replacing or removing and installing parts.

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  • 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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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

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

Tech Tips


  • Operating the engine 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 BRANCH WIRE)


    1. B008HESC03
      *a

      Front 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 Value
      I55-6 (CANH) - I55-5 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B008HESC04
      *a

      Front view of wire harness connector

      (to 4WD ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I55-4 (GND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

    2. Reconnect the cable to the negative (-) battery terminal.

      Note

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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      I55-3 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      Engine switch off Below 1 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE 4WD ECU ASSEMBLY for LHD: Click here
    REPLACE 4WD ECU ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)