CAN COMMUNICATION SYSTEM Driving Support ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Driving Support ECU Communication Stop Mode

Either condition is met:


  • "Driving Support (Cruise Control-ACC)" is not displayed on the CAN Bus Check screen of the GTS.

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

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  • Driving support ECU assembly branch line or connector

  • Power source circuit of driving support ECU assembly

  • Driving support ECU assembly ground circuit

  • Driving support ECU assembly

WIRING DIAGRAM

B007XXPE18

CAUTION / NOTICE / HINT

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 or any 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 negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) 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: Drive the vehicle at a speed of 36 km/h (22 mph) or more for 13 seconds or more, and with the dynamic radar cruise control system operated for 6 seconds 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.

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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 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 LINES (DRIVING SUPPORT ECU ASSEMBLY BRANCH LINE)


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

    2. B007WP2C03
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the A72 driving support ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-10 (CA2H) - A72-11 (CA2L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result Proceed to
      OK (w/o Stop and Start System) A
      OK (w/ Stop and Start System) B
      NG C

    B

    CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) Click here

    C

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY)

    A

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B007WP2C04
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-28 (GND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A72-7 (B) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Result
      OK
      NG

    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B007WP2C04
      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A72-28 (GND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A72-7 (B) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (B terminal) B
      NG (except B terminal) C

    A

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    B

    GO TO STOP AND START SYSTEM (FOR BACKUP BOOST CONVERTER CIRCUIT) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)