CAN COMMUNICATION SYSTEM Engine Stop and Start ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Engine Stop and Start ECU Communication Stop Mode

Any of the following conditions are met:


  • Communication stop for "Stop and Go/Start" is indicated on the "Communication Bus Check" screen of the GTS.

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  • Communication stop history for "Stop and Go/Start" is indicated on the "Communication Bus Check (Detail)" screen of the GTS. (The Lost Communication Time value for "Stop and Go/Start" is 6 or more.)

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

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  • Engine stop and start ECU branch line or connector

  • Power source circuit of engine stop and start ECU

  • Engine stop and start ECU ground circuit

  • Engine stop and start ECU

WIRING DIAGRAM

A001Y94E01

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 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: Turn the ignition switch ON and wait at least approximately 20 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 as normal.

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

Tech Tips


  • 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 (ENGINE STOP AND START ECU BRANCH LINE)


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

    2. A001SSMC25
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

      Disconnect the engine stop and start ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F77-13 (CANH) - F77-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (ENGINE STOP AND START ECU)

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Disconnect the engine stop and start ECU connector.

    2. A005Q5KC26
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A61-8 (GND1) -Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A61-3 (BIN1) - Body ground Always 11 to 14 V
      F77-18 (IG2) - Body ground Ignition switch ON 11 to 14 V
      F77-19 (ACC) - Body ground Ignition switch ACC 11 to 14 V
      F77-21 (IG1) - Body ground Ignition switch ON 11 to 14 V
      Result
      Result
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)