LEXUS PARKING ASSIST-SENSOR SYSTEM TERMINALS OF ECU


  1. CHECK CLEARANCE WARNING ECU

    A004YZ5E02

    1. Disconnect the A78 connector from the ECU.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      A78-12 (IG) - A78-27 (E) R - W-B IG power source signal Power switch off Below 1.5 V
      Power switch on (IG) 11 to 14 V
      A78-27 (E) - Body ground W-B - Body ground Ground Always Below 1 Ω
      A78-38 (CLSW) - A78-27 (E) BR - W-B Clearance sonar main switch power source signal

      • Power switch on (IG)

      • Clearance sonar main switch on

      		 11 to 14 V

      • Power switch on (IG)

      • Clearance sonar main switch off

      		 Below 1 V

    3. Reconnect the A78 connector to the ECU.

    4. Measure the voltage, resistance and check for pulses according to the value(s) in the table below.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      A78-1 (S1) - A78-2 (E1) Y - R Sensor communication signal (Rear right sensor)

      • Power switch on (IG)

      • Clearance sonar main switch on

      • Reverse (R) has been selected

      Pulse generation

      (See waveform 1)
      A78-2 (E1) - A78-27 (E) R - W-B Ground for sensor (Rear right sensor) Always Below 1 V
      A78-3 (S2) - A78-4 (E2) P - L Sensor communication signal (Rear left sensor)

      • Power switch on (IG)

      • Clearance sonar main switch on

      • Reverse (R) has been selected

      Pulse generation

      (See waveform 1)
      A78-4 (E2) - A78-27 (E) L - W-B Ground for sensor (Rear left sensor) Always Below 1 V
      A78-6 (S3) - A78-7 (E3) B - W Sensor communication signal (Rear right center sensor)

      • Power switch on (IG)

      • Clearance sonar main switch on

      • Reverse (R) has been selected

      Pulse generation

      (See waveform 1)
      A78-7 (E3) - A78-27 (E) W - W-B Ground for sensor (Rear right center sensor) Always Below 1 V
      A78-8 (S4) - A78-9 (E4) V - LG Sensor communication signal (Rear left center sensor)

      • Power switch on (IG)

      • Clearance sonar main switch on

      • Reverse (R) has been selected

      Pulse generation

      (See waveform 1)
      A78-9 (E4) - A78-27 (E) LG - W-B Ground for sensor (Rear left center sensor) Always Below 1 V
      A78-11 (CBZ) - A78-10 (EF) G - L Ground for clearance warning buzzer Buzzer sounding

      Pulse generation

      (See waveform 2)
      A78-19 (S5) - A78-20 (E5) B - W Sensor communication signal (Front right sensor)

      • Power switch on (IG)

      • Clearance sonar main switch on

      • A shift state other than park (P) has been selected

      • Vehicle speed is less than approximately 10 km/h (6.2 mph)

      Pulse generation

      (See waveform 1)
      A78-20 (E5) - A78-27 (E) W - W-B Ground for sensor (Front right sensor) Always Below 1 V
      A78-21 (S6) - A78-22 (E6) P - V Sensor communication signal (Front left sensor)

      • Power switch on (IG)

      • Clearance sonar main switch on

      • A shift state other than park (P) has been selected

      • Vehicle speed is less than approximately 10 km/h (6.2 mph)

      Pulse generation

      (See waveform 1)
      A78-22 (E6) - A78-27 (E) V - W-B Ground for sensor (Front left sensor) Always Below 1 V

    5. Using an oscilloscope, check waveform 1.


      1. A004ZR9E03

        Waveform 1(Reference)

        Item Content
        Terminal No. (Symbol)

        A78-1 (S1) - A78-2 (E1)

        A78-3 (S2) - A78-4 (E2)

        A78-6 (S3) - A78-7 (E3)

        A78-8 (S4) - A78-9 (E4)
        Tool Setting 2 V/DIV., 100 μsec./DIV.
        Condition

        • Power switch on (IG)

        • Clearance sonar main switch on

        • Reverse (R) has been selected
        Item Content
        Terminal No. (Symbol)

        A78-19 (S5) - A78-20 (E5)

        A78-21 (S6) - A78-22 (E6)
        Tool Setting 2 V/DIV., 100 μsec./DIV.
        Condition

        • Power switch on (IG)

        • clearance sonar main switch on

        • A shift state other than park (P) has been selected

        • Vehicle speed is less than approximately 10 km/h (6.2 mph)

    6. Using an oscilloscope, check waveform 2.


      1. A004YL4E01

        Waveform 2(Reference)

        Item Content
        Terminal No. (Symbol) A78-11 (CBZ) - A78-10 (EF)
        Tool Setting 2 V/DIV., 500 μsec./DIV.
        Vehicle Condition Buzzer sounding