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ECU Power Source Circuit [09/2015 - 08/2019]: Procedure

  1. CHECK DRIVING SUPPORT ECU ASSEMBLY (B VOLTAGE) 
    1. Disconnect the A72 driving support ECU assembly connector.
      GTY664697Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driving Support ECU Assembly)
    2. Turn the engine switch on (IG).
    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
    4. Turn the engine switch off.
    5. Reconnect the A72 driving support ECU assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - BODY GROUND) 
    1. Disconnect the A72 driving support ECU assembly connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A72-28 (GND) - Body ground Always Below 1 Ω
    3. Connect the A72 driving support ECU assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [09/2015 - 08/2019] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR