SFI SYSTEM TERMINALS OF ECM

Tech Tips

The standard voltage between each pair of the ECM terminals is shown in the table below. The appropriate conditions for checking each pair of the terminals are also indicated. The result of checks should be compared with the standard voltage for that pair of the terminals, and displayed in the "Specified Condition" column. The illustration above can be used as a reference to identify the ECM terminal locations.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
A50-1 (BATT) - B31-16 (E1)	P - BR	Battery (for measuring battery voltage and for ECM memory)	Always	11 to 14 V
A50-2 (+B) - B31-16 (E1)	B - BR	Power source of ECM	Ignition switch ON	11 to 14 V
A50-3 (+B2) - B31-16 (E1)	B - BR	Power source of ECM	Ignition switch ON	11 to 14 V
B31-29 (+BM) - B31-16 (E1)	B - BR	Power source of throttle actuator	Always	11 to 14 V
B31-57 (IGT1) - B31-16 (E1)	R - BR	No. 1 ignition coil signal (No. 1 cylinder) (ignition signal)	Idling	Pulse generation (See waveform 1)
B31-56 (IGT2) - B31-16 (E1)	B - BR	No. 1 ignition coil signal (No. 2 cylinder) (ignition signal)	Idling	Pulse generation (See waveform 1)
B31-55 (IGT3) - B31-16 (E1)	G - BR	No. 1 ignition coil signal (No. 3 cylinder) (ignition signal)	Idling	Pulse generation (See waveform 1)
B31-54 (IGT4) - B31-16 (E1)	W - BR	No. 1 ignition coil signal (No. 4 cylinder) (ignition signal)	Idling	Pulse generation (See waveform 1)
B31-109 (VCNE) - B31-16 (E1)	B - BR	Power source of crankshaft position sensor	Ignition switch ON	4.5 to 5.5 V
B31-78 (NE+) - B31-110 (NE-)	R - Y	Crankshaft position sensor signal	Idling with warm engine	Pulse generation (See waveform 2)
B31-113 (VCV1) - B31-16 (E1)	R - BR	Power source of camshaft position sensor (for intake camshaft)	Ignition switch ON	4.5 to 5.5 V
B31-111 (VCE1) - B31-16 (E1)	W - BR	Power source of camshaft position sensor (for exhaust camshaft)	Ignition switch ON	4.5 to 5.5 V
B31-82 (VV1+) - B31-114 (VV1-)	B - W	Camshaft position sensor signal (for intake camshaft)	Idling with warm engine	Pulse generation (See waveform 3)
B31-80 (EV1+) - B31-112 (EV1-)	P - B	Camshaft position sensor signal (for exhaust camshaft)	Idling with warm engine	Pulse generation (See waveform 3)
B31-20 (#10) - B31-51 (E01)	B - W-B	Fuel injector assembly signal (No. 1 cylinder)	Ignition switch ON	11 to 14 V
B31-20 (#10) - B31-51 (E01)	B - W-B	Fuel injector assembly signal (No. 1 cylinder)	Idling	Pulse generation (See waveform 4)
B31-17 (#20) - B31-51 (E01)	Y - W-B	Fuel injector assembly signal (No. 2 cylinder)	Ignition switch ON	11 to 14 V
B31-17 (#20) - B31-51 (E01)	Y - W-B	Fuel injector assembly signal (No. 2 cylinder)	Idling	Pulse generation (See waveform 4)
B31-18 (#30) - B31-51 (E01)	G - W-B	Fuel injector assembly signal (No. 3 cylinder)	Ignition switch ON	11 to 14 V
B31-18 (#30) - B31-51 (E01)	G - W-B	Fuel injector assembly signal (No. 3 cylinder)	Idling	Pulse generation (See waveform 4)
B31-19 (#40) - B31-51 (E01)	W - W-B	Fuel injector assembly signal (No. 4 cylinder)	Ignition switch ON	11 to 14 V
B31-19 (#40) - B31-51 (E01)	W - W-B	Fuel injector assembly signal (No. 4 cylinder)	Idling	Pulse generation (See waveform 4)
B31-23 (HA1A) - B31-52 (E04)	R - W-B	Air fuel ratio sensor (sensor 1) heater operation signal	Ignition switch ON	11 to 14 V
B31-23 (HA1A) - B31-52 (E04)	R - W-B	Air fuel ratio sensor (sensor 1) heater operation signal	Idling	Pulse generation (See waveform 5)
B31-133 (A1A+) - B31-16 (E1)	B - BR	Air fuel ratio sensor (sensor 1) signal	Ignition switch ON	3.3 V^*1
B31-134 (A1A-) - B31-16 (E1)	W - BR	Air fuel ratio sensor (sensor 1) signal	Ignition switch ON	2.9 V^*1
B31-22 (HT1B) - B31-52 (E04)	L - W-B	Heated oxygen sensor (sensor 2) heater operation signal	Ignition switch ON	11 to 14 V
B31-22 (HT1B) - B31-52 (E04)	L - W-B	Heated oxygen sensor (sensor 2) heater operation signal	Idling	Below 3.0 V
B31-103 (OX1B) - B31-135 (EX1B)	B - Y	Heated oxygen sensor (sensor 2) signal	Engine speed maintained at 2500 rpm for 2 minutes after warming up engine	Pulse generation (See waveform 6)
B31-123 (KNK1) - B31-124 (EKNK)	W - B	Knock control sensor signal	Engine speed maintained at 4000 rpm after warming up engine	Pulse generation (See waveform 7)
A50-44 (SPD) - B31-16 (E1)	V - BR	Vehicle speed signal from combination meter assembly	Driving at 20 km/h (12 mph)	Pulse generation (See waveform 8)
B31-93 (THW) - B31-94 (ETHW)	B - BR	Engine coolant temperature sensor signal	Idling, engine coolant temperature 80°C (176°F)	0.2 to 1.0 V
B31-90 (THA) - B31-122 (ETHA)	L - W	Intake air temperature sensor signal	Idling, intake air temperature 20°C (68°F)	0.5 to 3.4 V
B31-91 (VG) - B31-92 (E2G)	V - B	Mass air flow meter sub-assembly signal	Idling, shift lever in neutral, A/C switch off	0.5 to 3.0 V
A50-27 (W) - B31-16 (E1)	LG - BR	Malfunction Indicator Lamp (MIL) operation signal	Ignition switch ON (MIL goes on)	Below 3.0 V
A50-27 (W) - B31-16 (E1)	LG - BR	Malfunction Indicator Lamp (MIL) operation signal	Idling	11 to 14 V
A50-22 (STA) - B31-16 (E1)	LG - BR	Starter assembly signal	Cranking	6 V or higher
B31-63 (NSW) - B31-16 (E1)	W - BR	Clutch start switch assembly signal	Ignition switch ON, clutch pedal fully depressed	Below 1.5 V
B31-63 (NSW) - B31-16 (E1)	W - BR	Clutch start switch assembly signal	Ignition switch ON, clutch pedal fully released	11 to 14 V
B31-84 (VTA1) - B31-116 (ETA)	LG - L	Throttle position sensor signal (for engine control)	Ignition switch ON, accelerator pedal fully released	0.5 to 1.1 V
B31-84 (VTA1) - B31-116 (ETA)	LG - L	Throttle position sensor signal (for engine control)	Ignition switch ON, accelerator pedal fully depressed	3.2 to 4.8 V
B31-83 (VTA2) - B31-116 (ETA)	R - L	Throttle position sensor signal (for sensor malfunction detection)	Ignition switch ON, accelerator pedal fully released	2.1 to 3.1 V
B31-83 (VTA2) - B31-116 (ETA)	R - L		Ignition switch ON, accelerator pedal fully depressed	4.6 to 5.0 V
B31-115 (VCTA) - B31-116 (ETA)	Y - L	Power source of throttle position sensor (specific voltage)	Ignition switch ON	4.5 to 5.5 V
A50-53 (VCPA) - A50-52 (EPA)	B - Y	Power source of accelerator pedal position sensor (for VPA)	Ignition switch ON	4.5 to 5.5 V
A50-51 (VPA) - A50-52 (EPA)	W - Y	Accelerator pedal position sensor signal (for engine control)	Ignition switch ON, accelerator pedal fully released	0.5 to 1.1 V
A50-51 (VPA) - A50-52 (EPA)	W - Y		Ignition switch ON, accelerator pedal fully depressed	2.6 to 4.5 V
A50-54 (VPA2) - A50-55 (EPA2)	R - P	Accelerator pedal position sensor signal	Ignition switch ON, accelerator pedal fully released	1.2 to 2.0 V
A50-54 (VPA2) - A50-55 (EPA2)	R - P	Accelerator pedal position sensor signal	Ignition switch ON, accelerator pedal fully depressed	3.4 to 4.75 V
A50-56 (VCP2) - A50-55 (EPA2)	L - P	Power source of accelerator pedal position sensor (for VPA2)	Ignition switch ON	4.5 to 5.5 V
B31-60 (M+) - B31-59 (ME01)	P - W-B	Throttle actuator operation signal (positive terminal)	Idling with warm engine	Pulse generation (See waveform 9)
B31-30 (M-) - B31-59 (ME01)	V - W-B	Throttle actuator operation signal (negative terminal)	Idling with warm engine	Pulse generation (See waveform 10)
A50-9 (STP) - B31-16 (E1)	L2 - BR LG3 - BR	Stop light switch assembly signal	Brake pedal depressed	7.5 to 14 V
A50-9 (STP) - B31-16 (E1)	L2 - BR LG3 - BR	Stop light switch assembly signal	Brake pedal released	Below 1.5 V
A50-10 (ST1-) - B31-16 (E1)	R - BR	Stop light switch assembly signal (opposite to voltage at STP terminal)	Ignition switch ON, brake pedal depressed	Below 1.5 V
A50-10 (ST1-) - B31-16 (E1)	R - BR		Ignition switch ON, brake pedal released	7.5 to 14 V
B31-76 (PRG) - B31-16 (E1)	L - BR	Purge VSV operation signal	Ignition switch ON	11 to 14 V
B31-76 (PRG) - B31-16 (E1)	L - BR	Purge VSV operation signal	Idling, under purge control	Pulse generation (See waveform 11)
A50-21 (FC) - B31-16 (E1)	R - BR	Fuel pump control signal	Ignition switch ON	11 to 14 V
A50-21 (FC) - B31-16 (E1)	R - BR	Fuel pump control signal	Idling	Below 1.5 V
A50-31 (TACH) - B31-16 (E1)	GR - BR	Engine speed signal	Idling	Pulse generation (See waveform 12)
A50-23 (TC) - B31-16 (E1)	P - BR	Terminal TC of DLC3	Ignition switch ON	11 to 14 V
B31-75 (OC1+) - B31-74 (OC1-)	B - Y	Camshaft timing oil control valve assembly (for intake camshaft) operation signal	Idling	Pulse generation (See waveform 13)
B31-65 (OE1+) - B31-64 (OE1-)	G - P	Camshaft timing oil control valve assembly (for exhaust camshaft) operation signal	Idling	Pulse generation (See waveform 14)
A50-13 (CANH) - B31-16 (E1)	B - BR	CAN communication line	Ignition switch ON	Pulse generation (See waveform 15)
A50-12 (CANP)*4 - B31-16 (E1)	B - BR	CAN communication line	Ignition switch ON	Pulse generation (See waveform 15)
A50-26 (CANL) - B31-16 (E1)	W - BR	CAN communication line	Ignition switch ON	Pulse generation (See waveform 16)
A50-25 (CANN)*4 - B31-16 (E1)	SB - BR	CAN communication line	Ignition switch ON	Pulse generation (See waveform 16)
B31-79 (R) - B31-16 (E1)	L - BR	Back-up light switch assembly signal	Back-up light switch assembly on	11 to 14 V
B31-100 (ALT)*5 - B31-16 (E1)	L - BR	Generator assembly	Ignition switch ON	11 to 14 V
A50-37 (IGSW) - B31-16 (E1)	B - BR	Ignition switch signal	Ignition switch ON	11 to 14 V
A50-46 (MREL) - B31-16 (E1)	L - BR	EFI-MAIN relay operation signal	Ignition switch ON	11 to 14 V
A50-17 (ELS2) - B31-16 (E1)	L - BR	Electric load signal	Rear window defogger switch on	11 to 14 V
A50-17 (ELS2) - B31-16 (E1)	L - BR	Electric load signal	Rear window defogger switch off	Below 1.5 V
B31-28 (EGR1) - B31-16 (E1)	L - BR	EGR valve assembly operation signal	EGR valve assembly operating	Pulse generation (See waveform 17)
B31-27 (EGR2) - B31-16 (E1)	G - BR	EGR valve assembly operation signal	EGR valve assembly operating	Pulse generation (See waveform 18)
B31-26 (EGR3) - B31-16 (E1)	W - BR	EGR valve assembly operation signal	EGR valve assembly operating	Pulse generation (See waveform 17)
B31-25 (EGR4) - B31-16 (E1)	R - BR	EGR valve assembly operation signal	EGR valve assembly operating	Pulse generation (See waveform 18)
A50-45 (RFC) - B31-16 (E1)	R - BR	Cooling fan control signal	Ignition switch ON, A/C switch on (max cool)	Pulse generation (See waveform 19)
B31-118 (VCPM) - B31-119 (EPIM)	R - Y	Power source of manifold absolute pressure sensor	Ignition switch ON	4.75 to 5.25 V
B31-87 (PIM) - B31-119 (EPIM)	V - Y	Manifold absolute pressure sensor signal	Ignition switch ON	3.0 to 5.0 V
A50-30 (NEO) - B31-16 (E1)	L - BR	Crankshaft position sensor signal	Idling with warm engine	Pulse generation (See waveform 20)
A50-50 (EC) - Body ground	BR - -	Earth (ground) circuit of ECM	Always	Below 1 Ω
B31-51 (E01) - Body ground	W-B - -	Earth (ground) circuit of ECM	Always	Below 1 Ω
B31-21 (E02) - Body ground	W-B - -	Earth (ground) circuit of ECM	Always	Below 1 Ω
B31-59 (ME01) - Body ground	W-B - -	Earth (ground) circuit of ECM	Always	Below 1 Ω
B31-58 (GE01) - Body ground	BR - -	Shielded earth (ground) circuit of throttle actuator	Always	Below 1 Ω

*1: The ECM terminal voltage is constant regardless of the output voltage from the sensor.
*2: for Hatchback, Wagon models.
*3: for Sedan models.
*4: w/ Generator Control System.
*5: w/o Generator Control System.

WAVEFORM 1


*a	5 V/DIV.
*b	20 ms./DIV.

No. 1 Ignition Coil Signal (IGT Signal)
ECM Terminal Name	Between IGT (1 to 4) and E1
Tester Range	5 V/DIV., 20 ms./DIV.
Condition	Idling

Tech Tips

The wavelength becomes shorter as the engine speed increases.

WAVEFORM 2


*a	2 V/DIV.
*b	20 ms./DIV.

Crankshaft Position Sensor Signal
ECM Terminal Name	Between NE+ and NE-
Tester Range	2 V/DIV., 20 ms./DIV.
Condition	Idling with warm engine

Tech Tips

The wavelength becomes shorter as the engine speed increases.

WAVEFORM 3


*a	5 V/DIV.
*b	20 ms./DIV.

Camshaft Position Sensor Signal (for Intake and Exhaust Camshaft)
ECM Terminal Name	CH1: Between VV1+ and VV1- CH2: Between EV1+ and EV1-
Tester Range	5 V/DIV., 20 ms./DIV.
Condition	Idling with warm engine

Tech Tips

The wavelength becomes shorter as the engine speed increases.

WAVEFORM 4


*1	20 V/DIV.
*2	20 ms./DIV.

Fuel Injector Assembly Signal
ECM Terminal Name	Between #10 (to #40) and E01
Tester Range	20 V/DIV., 20 ms./DIV.
Condition	Idling

Tech Tips

The wavelength becomes shorter as the engine speed increases.

WAVEFORM 5


*a	5 V/DIV.
*b	10 ms./DIV.

Air Fuel Ratio Sensor (Sensor 1) Heater Operation Signal
ECM Terminal Name	Between HA1A and E04
Tester Range	5 V/DIV., 10 ms./DIV.
Condition	Idling

WAVEFORM 6


*1	0.2 V/DIV.
*2	200 ms./DIV.

Heated Oxygen Sensor (Sensor 2) Signal
ECM Terminal Name	Between OX1B and EX1B
Tester Range	0.2 V/DIV., 200 ms./DIV.
Condition	Engine speed maintained at 2500 rpm for 2 minutes after warming up engine

Tech Tips

In the Data List, the item O2S B1S2 shows the values input to the ECM from the heated oxygen sensor.

WAVEFORM 7


*a	1 V/DIV.
*b	1 ms./DIV.

Knock Control Sensor Signal
ECM Terminal Name	Between KNK1 and EKNK
Tester Range	1 V/DIV., 1 ms./DIV.
Condition	Engine speed maintained at 4000 rpm after warming up engine

Tech Tips

The wavelength becomes shorter as the engine speed increases.
The waveforms and amplitudes displayed differ slightly depending on the vehicle condition.

WAVEFORM 8


*a	5 V/DIV.
*b	20 ms./DIV.

Vehicle Speed Signal
ECM Terminal Name	Between SPD and E1
Tester Range	5 V/DIV., 20 ms./DIV.
Condition	Driving at 20 km/h (12 mph)

Tech Tips

The wavelength becomes shorter as the vehicle speed increases.

WAVEFORM 9


*a	5 V/DIV.
*b	1 ms./DIV.

Throttle Actuator Positive Terminal Signal
ECM Terminal Name	Between M+ and ME01
Tester Range	5 V/DIV., 1 ms./DIV.
Condition	Idling with warm engine

Tech Tips

The duty ratio varies depending on the throttle actuator operation.

WAVEFORM 10


*a	5 V/DIV.
*b	1 ms./DIV.

Throttle Actuator Negative Terminal Signal
ECM Terminal Name	Between M- and ME01
Tester Range	5 V/DIV., 1 ms./DIV.
Condition	Idling with warm engine

Tech Tips

The duty ratio varies depending on the throttle actuator operation.

WAVEFORM 11


*1	10 V/DIV.
*2	20 ms./DIV.

Purge VSV Operation Signal
ECM Terminal Name	Between PRG and E1
Tester Range	10 V/DIV., 20 ms./DIV.
Condition	Idling, under purge control

Tech Tips

If the waveform is not similar to the illustration, check the waveform again after idling for 10 minutes or more.

WAVEFORM 12


*a	5 V/DIV.
*b	10 ms./DIV.

Engine Speed Signal
ECM Terminal Name	Between TACH and E1
Tester Range	5 V/DIV., 10 ms./DIV.
Condition	Idling

Tech Tips

The wavelength becomes shorter as the engine speed increases.

WAVEFORM 13


*a	5 V/DIV.
*b	1 ms./DIV.

Camshaft Timing Oil Control Valve Assembly (for Intake Camshaft) Operation Signal
ECM Terminal Name	Between OC1+ and OC1-
Tester Range	5 V/DIV., 1 ms./DIV.
Condition	Idling

WAVEFORM 14


*a	5 V/DIV.
*b	1 ms./DIV.

Camshaft Timing Oil Control Valve Assembly (for Exhaust Camshaft) Operation Signal
ECM Terminal Name	Between OE1+ and OE1-
Tester Range	5 V/DIV., 1 ms./DIV.
Condition	Idling

WAVEFORM 15


*a	1 V/DIV.
*b	10 μs./DIV.

CAN Communication Signal (Reference)
ECM Terminal Name	Between CANH and E1, or CANP and E1
Tester Range	1 V/DIV., 10 μs./DIV.
Condition	Ignition switch ON

Tech Tips

The waveform varies depending on the CAN communication signal.

WAVEFORM 16


*a	1 V/DIV.
*b	10 μs./DIV.

CAN Communication Signal (Reference)
ECM Terminal Name	Between CANL and E1, or CANN and E1
Tester Range	1 V/DIV., 10 μs./DIV.
Condition	Ignition switch ON

Tech Tips

The waveform varies depending on the CAN communication signal.

WAVEFORM 17


*1	10 V/DIV.
*2	20 ms./DIV.

EGR Valve Assembly Operation Signal
ECM Terminal Name	CH1: Between EGR1 and E1 CH2: Between EGR3 and E1
Tester Range	10 V/DIV., 20 ms./DIV.
Condition	EGR valve assembly operating

WAVEFORM 18


*1	10 V/DIV.
*2	20 ms./DIV.

EGR Valve Assembly Operation Signal
ECM Terminal Name	CH1: Between EGR2 and E1 CH2: Between EGR4 and E1
Tester Range	10 V/DIV., 20 ms./DIV.
Condition	EGR valve assembly operating

WAVEFORM 19


*a	1 V/DIV.
*b	2 ms./DIV.

Cooling Fan Control Signal
ECM Terminal Name	Between RFC and E1
Tester Range	1 V/DIV., 2 ms./DIV.
Condition	Ignition switch ON, A/C switch on (max cool)

Tech Tips

The duty ratio varies depending on the engine coolant temperature.

WAVEFORM 20


*a	1 V/DIV.
*b	2 ms./DIV.

Crankshaft Position Sensor Signal
ECM Terminal Name	Between NEO and E1
Tester Range	1 V/DIV., 2 ms./DIV.
Condition	Idling with warm engine

Tech Tips

The wavelength becomes shorter as the engine speed increases.