CAN COMMUNICATION SYSTEM(for LHD) Air Conditioning Amplifier Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Air Conditioning Amplifier Communication Stop Mode

Either condition is met:


  • "Air Conditioning Amplifier" is not displayed on "CAN Bus Check".

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

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  • Power source circuit of air conditioning amplifier assembly

  • Air conditioning amplifier assembly ground circuit

  • Air conditioning amplifier assembly CAN branch wire or connector

  • Air conditioning amplifier assembly

WIRING DIAGRAM

A01XOZHE72

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

  • DTC check procedure: Turn the engine switch on (IG) and wait at least 20 seconds.

  • 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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  • When the battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.

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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 (AIR CONDITIONING AMPLIFIER ASSEMBLY BRANCH WIRE)


    1. B005A9VC05
      *a

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

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

    2. Disconnect the air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I50-11 (CANH) - I50-12 (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 (AIR CONDITIONING AMPLIFIER ASSEMBLY)

    OK

  2. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - BATTERY AND BODY GROUND)


    1. A01XOMLC06
      *a

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      I50-21 (B) - Body ground Always 11 to 14 V
      I50-1 (IG+) - Body ground Engine switch on (IG) 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I50-14 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR