Terminals Of Ecu: Notes

Fig 1: Identifying C8 Meter Connector

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1. Disconnect the C8 meter connector.
2. Measure the voltage and resistance of the wire harness side connector.

   Standard: 

   ECU CONNECTOR TERMINAL VOLTAGE SPECIFICATION
   
   

   Symbols (Terminal No.)	Wiring Color	Terminal Description	Condition	Specified Condition
   IG+ (C8-1) - Body ground	R-Y - Body ground	Ignition switch power supply	Ignition switch OFF	Below 1 V
   IG+ (C8-1) - Body ground	R-Y - Body ground	Ignition switch power supply	Ignition switch ON	10 to 14 V
   ES (C8-12) - Body ground	BR - Body ground	Ground	Always	Below 1 Ω
   B (C8-13) - Body ground	B - Body ground	Battery	Always	10 to 14 V

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

3. Reconnect the C8 meter connector.
4. Measure the voltage of the connector.
   ECU CONNECTOR TERMINAL VOLTAGE SPECIFICATION
   
   

   Symbols (Terminal No.)	Wiring Color	Terminal Description	Condition	Specified Condition
   MPX+ (C8-3) - ES (C8-12)	Y - BR	Multiplex network communication signal	-	-
   MPX+ (C8-4) - ES (C8-12)	L-O - BR	Multiplex network communication signal	-	-
   S (C8-5) - ES (C8-12)	B-Y - BR	Tachometer signal (Input)	Engine running	Pulse generation (see )
   CHK (C8-6) - Body ground	R-B - Body ground	MIL warning signal	Ignition switch ON, MIL OFF	10 to 14 V
   CHK (C8-6) - Body ground	R-B - Body ground	MIL warning signal	Ignition switch ON, MIL ON	Below 1 V
   A/B (C8-8) - ES (C8-12)	R - BR	ODO/TRIP signal	Ignition switch ON, ODO/TRIP not pressed	Below 1 V
   A/B (C8-8) - ES (C8-12)	R - BR	ODO/TRIP signal	Ignition switch ON, ODO/TRIP pressed	4.5 to 5.5 V
   RSET (C8-9) - ES (C8-12)	P - BR	RESET signal	Ignition switch ON, RESET not pressed	Below 1 V
   RSET (C8-9) - ES (C8-12)	P - BR	RESET signal	Ignition switch ON, RESET pressed	4.5 to 5.5 V
   PBLT (C8-10) - Body ground	L-R - Body ground	Passenger side seat belt warning signal	Ignition switch ON, passenger side seat belt unfastened (ON)	10 to 14 V
   PBLT (C8-10) - Body ground	L-R - Body ground	Passenger side seat belt warning signal	Ignition switch ON, passenger side seat belt fastened (OFF)	Below 1 V
   TURN L (C8-15) - Body ground	G-B - Body ground	Turn signal indicator LH signal	Ignition switch ON, turn signal indicator lamp LH OFF	10 to 14 V
   TURN L (C8-15) - Body ground	G-B - Body ground	Turn signal indicator LH signal	Ignition switch ON, turn signal indicator lamp LH ON	Below 1 V
   TURN R (C8-16) - Body ground	G-Y - Body ground	Turn signal indicator RH signal	Ignition switch ON, turn signal indicator lamp RH OFF	10 to 14 V
   TURN R (C8-16) - Body ground	G-Y - Body ground	Turn signal indicator RH signal	Ignition switch ON turn signal indicator lamp RH ON	Below 1 V
   ILL- (C8-18) - Body ground	W-L - Body ground	Rheostat signal	Ignition switch ON	Pulse generation
   S1 (C8-20) - Body ground	V - Body ground	Vehicle speed signal (output)	Ignition switch ON, slowly turn rear wheel	Pulse generation (see )
   +S (C8-21) - Body ground	W-R - Body ground	Vehicle speed signal (output)	Ignition switch ON, slowly turn rear wheel	Pulse generation (see )
   FR (C8-22) - FE (C8-23)	Y-R - Y-G	Fuel sender gauge signal	Ignition switch ON, fuel level F	0.5 V

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

   Waveform 1 (Reference): 

   VOLTAGE REFERENCE (WAVEFORM 1)
   
   

   Symbols (Terminal No.)	S (C8-5) - ES (C8-12)
   Tester Range	5 V/DIV., 10 msec./DIV.
   Vehicle Condition	Driving at approx. 20 km/h (12 mph)

   HINT:

   As engine speed increases, the wavelength shortens.

   Fig 2: Identifying Waveform 1

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Waveform 2 (Reference): 

   VOLTAGE REFERENCE (WAVEFORM 2)
   
   

   Symbols (Terminal No.)	S1 (C8-20) - Body ground
   Tester Range	5 V/DIV., 20 msec./DIV.
   Vehicle Condition	Engine idling

HINT:

As engine speed increases, the wavelength shortens.

Fig 3: Identifying Waveform 2

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002