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Engine Stop and Start ECU Communication Stop Mode [11/2023 - ]: 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. Disconnect the H66 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
      H66-13 (CANH) - H66-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      GTY1178385Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Engine Stop and Start ECU)

      Result

      Proceed to 
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the A33 and A34 engine stop and start ECU connectors.
      GTY1177998Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Engine Stop and Start ECU)      		 - -
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A33-2 (GND2) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      A33-8 (GND1) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      A34-6 (DGND) - 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 Condition Specified Condition
      A33-1 (BIN2) - Body ground Always 9.5 to 14 V
      A33-3 (BIN1) - Body ground Always 9.5 to 14 V
      A34-1 (+B) - Body ground Ignition switch ON 9.5 to 14 V
      H66-18 (IGP) - Body ground Ignition switch ON 9.5 to 14 V
      H66-19 (ACC) - Body ground Ignition switch ACC 9.5 to 14 V
      H66-21 (IGR) - Body ground Ignition switch ON 9.5 to 14 V

      Result

      Proceed to 
      OK
      NG

    Result: 

    OK 

    REPLACE ENGINE STOP AND START ECU 

    Refer to REMOVAL [11/2023 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

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