LEXUS PARKING ASSIST-SENSOR SYSTEM > TERMINALS OF ECU

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CHECK CLEARANCE WARNING ECU

E149991E17

  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.



      E168464E01

    1. 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.



      E168463E01

    1. Waveform 2 (Reference)
      Item
      		Content
      Terminal No. (Symbol)
      1. CH: 1 A49-8 (SOF) - A49-21 (E)
      2. 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