Terminals Of Ecu: Notes

Fig 1: Identifying Terminals Of ECU Connector

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1. Disconnect the C37 combination meter assembly connector.
2. Measure the voltage according to the value(s) in the table below.
   TERMINALS VOLTAGE CHART
   
   

   Terminal No. (Symbols)	Wiring Color	Terminal Description	Condition	Specified Condition
   C37-1 (B) - Body ground	W - Body ground	Battery	Always	11 to 14 V
   C37-2 (IG+) - Body ground	P - Body ground	Ignition switch signal	Ignition switch OFF → ON	Below 1V → 11 to 14 V
   C37-24 (ET) - Body ground	BR - Body ground	Ground	Always	Below 1 V

   If the result is not as specified, there may be a malfunction on the wire harness side.

3. Reconnect the C37 combination meter assembly connector
4. Measure the voltage according to the value(s) in the table below.
   TERMINALS VOLTAGE CHART
   
   

   Terminal No. (Symbols)	Wiring Color	Terminal Description	Condition	Specified Condition
   C36-1 (CHG-) - Body ground	Y - Body ground	Charge warning light signal	Engine start, Charge warning light OFF → ON	Below 1 V → 11 to 14 V
   C36-2 (SW) - Body ground	Y - Body ground	Brake fluid level warning light signal	Ignition switch on (IG), Brake fluid level warning light ON	Below 1 V → 11 to 14 V
   C36-3 (EFI) - Body ground	P - Body ground	Check engine warning light signal	Check engine warning light OFF → ON	Below 1 V → 11 to 14 V
   C36-5 (S) - Body ground	Y - Body ground	Engine oil pressure signal	Engine oil pressure signal OFF → ON	Below 1 V → 11 to 14 V
   C36-9 (WRNP)-Body ground	0 - Body ground	Seat belt warning signal (Passenger side)	Ignition switch on (IG), Front passenger seat belt warning light OFF → ON → OFF	Below 1 V → 11 to 14 V → Below 1 V
   C36-12 (-) - Body ground	W-B - Body ground	Hi beam signal	BEAM indicator light signal OFF-4 ON	Below 1V → 11 to 14 V
   C36-14 (+) - Body ground	R - Body ground	Hi beam signal	BEAM indicator light signal OFF → ON	Below 1 V → 11 to 14 V
   C36-15 (B) - Body ground	L - Body ground	Right turn signal	Right turn indicator light OFF → ON	Below 1 V → 11 to 14 V
   C36-16 (B) - Body ground	Y - Body ground	Left turn signal	Left turn indicator light OFF → ON	Below 1 V → 11 to 14 V
   C37-6 (ILL-) - Body ground	W - Body ground	Light control rheostat signal	Ignition switch OFF → ON (IG)	Pulse generation (See  1waveform 1)
   C37-9 (TIRE) - Body ground	P - Body ground	Tire pressure warning light signal	Ignition switch on (IG), Tire pressure warning light ON	0 9 to 3 2 V
   			Ignition switch on (IG), Tire pressure warning light OFF	3 2 V or higher
   C37-11 (CANH) - Body ground	G - Body ground	CAN communication line	Ignition switch on (IG)	Pulse generation
   C37-12 (CANL) - Body ground	W - Body ground	CAN communication line	Ignition switch on (IG)	Pulse generation
   C37-13 (ILL+) - Body ground	G - Body ground	Tail switch signal	Tail switch OFF → ON	Below 1 V → 11 to 14 V
   C37-14 (TC) - Body ground	G - Body ground	Tail cancel switch signal	Ignition switch on (IG), tail cancel switch OFF	4 to 6 V
   			Ignition switch on (IG), tail cancel switch ON	Below 1 V
   C37-17 (L) - Body ground	Y - Body ground	Fuel signal	Ignition switch on (IG), Fuel level is FULL	Below 1 V
   			Ignition switch on (IG), Fuel level is EMPTY	3 to 7 V
   C37-18 (TEMP) - Body ground	W - Body ground	Outside temperature signal	Ignition switch on (IG), outside temperature 25°C	Approx 1 3V
   C37-19 (SI) - Body ground	V - Body ground	Vehicle speed signal (Input)	Ignition switch on (IG), Slowly turn wheel	Pulse generation (See  2waveform 2)
   C37-20 (+S) - Body ground	V - Body ground	Vehicle speed signal (Output)	Vehicle is driven	Pulse generation (See  2waveform 2)
   C37-22 (E) - Body ground	BR - Body ground	Ground (Fuel ground)	Always	Below 1 V
   C37-23 (TX1) - Body ground	G - Body ground	Ground (Temperature ground)	Always	Below 1 V

   If the result is not as specified, the combination meter may be malfunctioning.

   1. Waveform 1: Using an oscilloscope
      WAVEFORM 1 REFERENCE
      
      

      Terminal Connections	C37-6 (ILL-) - Body Ground
      Tester Range	5V/DIV, 50msec/DIV
      Vehicle Condition	Ignition switch on (IG)

      Fig 2: Identifying Waveform 1

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   2. Waveform 2: Using an oscilloscope
      WAVEFORM 2 REFERENCE
      
      

      Terminal Connections	C37-19 (SI) - Body ground C37-20 (+S) - Body ground
      Tester Range	5V/DIV, 20msec/DIV
      Vehicle Condition	Driving at approximately 12mph (20km/ h)

      Fig 3: Identifying Waveform 2

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      HINT:

      As the vehicle speed increases, the cycle of the signal waveform narrows.

Fig 4: Identifying Main Body ECU Connector Terminals (1 Of 2)

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Fig 5: Identifying Main Body ECU Connector Terminals (2 Of 2)

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Standard: 

If the result is not as specified, there may be a malfunction in the wire harness.

Fig 6: Meter / Gauge System Circuit Diagram (1 Of 3)

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Fig 7: Meter / Gauge System Circuit Diagram (2 Of 3)

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Fig 8: Meter / Gauge System Circuit Diagram (3 Of 3)

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