LEXUS PARKING ASSIST-SENSOR SYSTEM TERMINALS OF ECU


  1. CHECK CLEARANCE WARNING ECU

    A003YMNE17

    1. Disconnect the A49 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
      A49-1 (CLSW) - A49-21 (E) BR - W-B Back sonar or clearance sonar switch power source signal Power switch on (IG), back sonar or clearance sonar switch on 11 to 14 V
      A49-1 (CLSW) - A49-21 (E) BR - W-B Back sonar or clearance sonar switch power source signal Power switch on (IG), back sonar or clearance sonar switch off Below 1 V
      A49-10 (IG) - A49-21 (E) R - W-B IG power source signal Power switch off Below 1.5 V
      Power switch on (IG) 11 to 14 V
      A49-21 (E) - Body ground W-B - Body ground Ground Always Below 1 Ω

    3. Reconnect the A49 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
      A49-7 (BOR) - A49-21 (E) Y - W-B Power source for rear sensor circuit Power switch off Below 1.5 V
      Power switch on (READY), LEXUS parking assist-sensor system on 7.2 to 8.8 V
      A49-8 (SOF) - A49-21 (E) G - W-B Front sensor communication signal (Front clearance sonar sensor) Power switch on (READY), LEXUS parking assist-sensor system on, Reverse (R) selected

      Pulse generation

      (See waveform 2)
      A49-12 (CBZ) - A49-21 (E) L - W-B Ground for clearance warning buzzer Buzzer sounding

      Pulse generation

      (See waveform 1)
      A49-22 (E1) - A49-21 (E) W - W-B Ground for rear clearance sonar Always Below 1 Ω
      A49-24 (E5) - A49-21 (E) W - W-B Ground for front clearance sonar Always Below 1 Ω
      A49-9 (BOF) - A49-21 (E) B - W-B Power source for front sensor circuit Power switch off Below 1.5 V
      Power switch on (READY), LEXUS parking assist-sensor system on 7.2 to 8.8 V
      A49-6 (SOR) - A49-21 (E) R - W-B Rear sensor communication signal (Rear clearance sonar sensor) Power switch on (READY), LEXUS parking assist-sensor system on, Reverse (R) selected

      Pulse generation

      (See waveform 2)

    5. Using an oscilloscope, check waveform 1.


      1. A003WNNE01

        Waveform 1 (Reference)

        Item Content
        Terminal No. (Symbol) A49-12 (CBZ) - A49-21 (E)
        Tool Setting 2 V/DIV., 500 μsec./DIV.
        Vehicle Condition When sonar detects obstacle (buzzer sounds)

    6. Using an oscilloscope, check waveform 2.


      1. A003ZN7E01

        Waveform 2 (Reference)

        Item Content
        Terminal No. (Symbol)

        • CH: 1 A49-8 (SOF) - A49-21 (E)

        • CH: 2 A49-6 (SOR) - A49-21 (E)
        Tool Setting 5 V/DIV., 1 msec./DIV.
        Condition Power switch on (READY), LEXUS parking assist-sensor system on, Reverse (R) selected