PRE-COLLISION SYSTEM TERMINALS OF ECU

CHECK DRIVING SUPPORT ECU ASSEMBLY

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

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   F128-7 (B) - F128-28 (GND)	R - W-B	Power source	Engine switch on (IG)	11 to 14 V
   			Engine switch off	Below 1 V
   F128-3 (BZ) - F128-28 (GND)	L - W-B	Skid control buzzer assembly output	Engine switch on (IG), buzzer not sounding	11 to 14 V
   			Engine switch on (IG), buzzer sounding	Below 1 V
   F128-28 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

2. Check for pulses according to the value(s) in the table below.

   Tech Tips

   If the waveform is not similar to that shown in the illustration, a malfunction of a CAN bus line, terminating resistor, or the driving support ECU assembly is suspected.

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   F128-8 (CA1P) - F128-28 (GND)	B - W-B	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 1)
   F128-9 (CA1N) - F128-28 (GND)	W - W-B	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 2)
   F128-10 (CA2H) - F128-28 (GND)	G - W-B	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 1)
   F128-11 (CA2L) - F128-28 (GND)	W - W-B	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 2)

   
   
   1. 

      *a	1 V/DIV.
      *b	10 μsec./DIV.

      WAVEFORM 1

      Item	Content
      Terminal Name	Between F128-8 (CA1P) - F128-28 (GND) Between F128-10 (CA2H) - F128-28 (GND)
      Tester Range	1 V/DIV., 10 μsec./DIV.
      Condition	Engine switch on (IG)

      Tech Tips

      The waveform varies depending on the CAN communication signal.

   2. 

      *a	1 V/DIV.
      *b	10 μsec./DIV.

      WAVEFORM 2

      Item	Content
      Terminal Name	Between F128-9 (CA1N) - F128-28 (GND) Between F128-11 (CA2L) - F128-28 (GND)
      Tester Range	1 V/DIV., 10 μsec./DIV.
      Condition	Engine switch on (IG)

      Tech Tips

      The waveform varies depending on the CAN communication signal.

CHECK MILLIMETER WAVE RADAR SENSOR ASSEMBLY

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

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   A81-8 (IGB) - A81-1 (SGND)	R - BR	Power source	Engine switch on (IG)	11 to 14 V
   A81-1 (SGND) - Body ground	BR - Body ground	Ground	Always	Below 1 Ω

2. Check for pulses according to the value(s) in the table below.

   Tech Tips

   If the waveform is not similar to that shown in the illustration, a malfunction of a CAN bus line, terminating resistor, or the millimeter wave radar sensor assembly is suspected.

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   A81-3 (CA2H) - A81-1 (SGND)	P - BR	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 1)
   A81-2 (CA2L) - A81-1 (SGND)	W - BR	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 2)
   A81-5 (CA1P) - A81-1 (SGND)	B - BR	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 1)
   A81-6 (CA1N) - A81-1 (SGND)	W - BR	CAN communication signal	Engine switch on (IG)	Pulse generation (See waveform 2)

   
   
   1. 

      *a	1 V/DIV.
      *b	10 μsec./DIV.

      WAVEFORM 1

      Item	Content
      Terminal Name	Between A81-3 (CA2H) and A81-1 (SGND) Between A81-5 (CA1P) and A81-1 (SGND)
      Tester Range	1 V/DIV., 10 μsec./DIV.
      Condition	Engine switch on (IG)

      Tech Tips

      The waveform varies depending on the CAN communication signal.

   2. 

      *a	1 V/DIV.
      *b	10 μsec./DIV.

      WAVEFORM 2

      Item	Content
      Terminal Name	Between A81-2 (CA2L) and A81-1 (SGND) Between A81-6 (CA1N) and A81-1 (SGND)
      Tester Range	1 V/DIV., 10 μsec./DIV.
      Condition	Engine switch on (IG)

      Tech Tips

      The waveform varies depending on the CAN communication signal.