CAN COMMUNICATION SYSTEM Driving Support ECU Communication Stop Mode

DTC Code DTC Name
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

C305470E01

CAUTION / NOTICE / HINT

Note:

  • 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 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 ignition 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: While driving the vehicle at a speed of 36 km/h (22 mph) or more, turn the cruise control system on using the cruise control switch (ON-OFF button) and drive the vehicle at the speed for at least 2.32 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.

Tip:

  • Operating the ignition 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. C285241C13

      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

      Disconnect the E128 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

      E128-39 (CANH) - E128-17 (CANL)

      Cable disconnected from negative (-) battery terminal

      54 to 69 Ω

    Result

    Result

    Result

    OK

    NG
    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    1. C285241C14

      *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

      E128-25 (GND) - Body ground

      Cable disconnected from negative (-) battery terminal

      Below 1 Ω

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

    3. C285241C15

      *a

      Front view of wire harness connector

      (to Driving Support ECU Assembly)

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      E128-30 (+B) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Result

    Result

    OK

    NG
    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY

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    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)