CAN COMMUNICATION SYSTEM(for LHD) DCM Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
DCM Communication Stop Mode

Either condition is met:


  • "DCM" is not displayed on "CAN Bus Check".

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

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  • Power source circuit of telematics transceiver

  • Telematics transceiver ground circuit

  • Telematics transceiver CAN branch wire or connector

  • Telematics transceiver

For vehicles with an emergency call switch.

WIRING DIAGRAM

A0000FPE08

CAUTION / NOTICE / HINT

Note


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

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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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 power switch on (IG) and wait at least 8.2 seconds.

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

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

  • Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for G-BOOK.

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Tech Tips


  • Operating the power 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 may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (TELEMATICS TRANSCEIVER BRANCH WIRE)


    1. B002IBPC06
      *a

      Front view of wire harness connector

      (to Telematics Transceiver)

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

    2. Disconnect the telematics transceiver connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I40-15 (CANP) - I40-16 (CANN) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (TELEMATICS TRANSCEIVER)

    OK

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


    1. A0001AQC07
      *a

      Front view of wire harness connector

      (to Telematics Transceiver)

      Reconnect the cable to the negative (-) auxiliary 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 Switch Condition Specified Condition
      I40-1 (+B) - Body ground Power switch off 11 to 14 V
      I40-7 (IG2) - Body ground Power switch on (IG) 11 to 14 V
      I40-8 (ACC) - Body ground Power switch on (ACC) 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I40-4 (E) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE TELEMATICS TRANSCEIVER Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR