1988 to 1995 Mustang ECU Pinouts

Courtesy of the Old Ford Fuel Injection Site Circa 199x-2003.

1988-1991-ish

Pin #	Connections for a 88-93 5.0L HO Mustang	Value @ Idle

01	+12 Battery Voltage	12-14 volts
03	VSS + / Vehicle Speed Sensor Positive	55MPH = 125hz
04	IDM / Ignition Diagnostic Monitor (TFI)	20-31hz
06	VSS - / Vehicle Speed Sensor Negative	55MPH = 125hz
07	ECT / Engine Coolant Temp Sensor	3 volts = 70*F
09	MAF RTN / Mass Air Flow Return	< 0.1volts (open to ground)
12	Fuel Injector 3	4.9-5.2ms duty cycle
13	Fuel Injector 4	4.9-5.2ms duty cycle
14	Fuel Injector 5	4.9-5.2ms duty cycle
15	Fuel Injector 6	4.9-5.2ms duty cycle
16	Ignition Ground (TFI)	< 0.1volts (open to ground)
17	MIL / Engine Light & STO / Self-Test Output (on self-test plug)	On=<1volt / Off=12-14volts
19	FPM / Fuel Pump Monitor	Pump on = 12-14volts
20	Case Ground	< 0.1volts (open to ground)
21	IAB / Idle Air Bypass	3.0 - 12.0 volts
22	FPR / Fuel Pump Relay	On=<1volt / Off=12-14volts
25	ACT / Air Charge Temp Sensor	3 volts = 70*F
26	Voltage Reference	4.9-5.1 volts
29	(R) HEGO	0.0-1.0 volts
30	Transmission Neutral Interface	0.0 volts in neutral
36	SPOUT / SPark angle OUT	6.93 volts
37	+12 volts	12-14 volts
40	Ground	< 0.1volts (open to ground)
42	Fuel Injector 7	4.9-5.2ms duty cycle
43	(L) HEGO	0.0-1.0 volts
45	BP / Barometric Pressure Sensor	159hz = sea level
46	Signal Return	< 0.1volts
47	TPS / Throttle Position Sensor	1.25 volts
48	STI / Self-Test Input	< 0.1volts
49	HEGO Ground	< 0.1volts (open to ground)
50	MAF / Mass Air Flow Sensor	0.8 volts
52	Fuel Injector 8	4.9-5.2ms duty cycle
56	PIP / Profile Ignition Pickup (TFI)	6.93 volts
57	+12 volts	12-14 volts
58	Fuel Injector 1	4.9-5.2ms duty cycle
59	Fuel Injector 2	4.9-5.2ms duty cycle
60	Ground	< 0.1volts (open to ground)

Signal Return

Voltage

Reference

Ground

+12Battery

Voltage

+12 Run

Voltage

Self-Test

MAP/BP

TPS

ACT

ECT

MAP/BP

TPS

EEC relay

Ignition Relay

MAF/HEGO Relay

EEC 20/40/60

EEC 30 (trans)

EEC 49 (HEGO)

TFI shielding

HEGO’s

MAF

EEC 1

Fuel Pump Relay

EEC Relay

Ignition Relay

MAF/HEGO Relay

EEC relay

Ignition Relay

MAF/HEGO Relay

Fuel Pump Relay

undocumented pins:
2 ( Not connected to any componets internally)
5 ( Not connected to any componets internally)
8( Not connected to any componets internally)
11( Not connected to any componets internally)
18( Not connected to any componets internally)
23( Not connected to any componets internally)
24 (4 has been used for the cam sensor (CID) on EDIS swaps)-unconfirmed
28( Not connected to any componets internally)
34( Connected to some componets) unsure what its for
35( Connected to some componets) unsure what its for
39 ( Connected to pin 40 internally- Ground)
41 ( High Speed Fan Enable)
44( Not connected to any componets internally)
51( Connected to some componets) unsure what its for
53( Not connected to any componets internally)
55( Connected to some componets)unsure what its for

	EEC Relay	Ignition Relay	MAF/HEGO Relay	Fuel Pump Relay
Pin 87	EEC 37/57 Ck Engine Light Fuel Injectors Idle Air Bypass	TFI Coil	MAF R HEGO L HEGO	Fuel Pump FPM (EEC pin 19)
Pin 30	Constant +12 Volts from Battery protected by Fuse
Pin 30	20AMP	20AMP	30AMP	20AMP
Pin 86	+12 Volts from Ignition Switch (Hot in Run and Start)
Pin 85	Ground	Ground	Ground	EEC pin 22

When installing the Ford Racing Performance Harness, this explains the connections needed within the harness

1992-1993

1	37	Y	Keep Alive Power	KAPWR
3	679	GY/BK	Vehicle Speed Sensor(+)	VSS+
4	11	T/Y	Ignition Diagnostic Monitor	IDM
6	676	PK/O	Vehicle Speed Sensor (-)	VSS-
7	354	LG/R	Engine Coolant Temp. Sensor	ECT
9	968	T/LB	Mass Air Flow Sensor Return	MAF RTN
10	347	BK/Y	A/C Clutch Signal	ACCS
12	557	BR/Y	Injector 3	INJ 3
13	558	BR/LB	Injector 4	INJ 4
14	559	T/BK	Injector 5	INJ 5
15	560	LG/O	Injector 6	INJ 6
16	259	O/R	Ignition Ground	IGN GND
17	658	PK/LG	Self-Test Output/Malfunction Ind.	STO/MIL
19	238	DG/Y	Fuel Pump Monitor	FPM
20	57	BK	Case Ground	CASE GND
21	264	W/LB	Idle Air Control Solenoid	IAC
22	926	LB/O	Fuel Pump	FP
25	743	GY	Intake Air Temp. Sensor	IAT
26	351	BR/W	Reference Voltage	VREF
27	352	BR/LG	EGR Valve Position Sensor	EVP
29	74	GY/LB	Heated Oxygen Sensor-Right	HO2S-R
30	199	LB/Y	Park/Neutral Position Switch	PNP
31	101	GY/Y	Canister Purge Solenoid	CANP
32	911	W/LG	Secondary Air Injection Diverter Solenoid	AIRD
33	360	BR/PK	EGR Vacuum Regulator Solenoid	EVR
36	929	PK	Spark Output	SPOUT
37	361	R	Vehicle Power	VPWR
38	925	W/Y	Secondary Air Injection Bypass Solenoid	AIRB
40	570	BK/W	Power Ground	PWR GND
42	561	T/R	Fuel Injector 7	INJ 7
43	94	R/BK	Heated Oxygen Sensor - Left	HO2S-L
45	358	LG/BK	Barometric Pressure Sensor	BARO
46	359	GY/R	Signal Return	SIG RTN
47	355	GY/W	Throttle Position Sensor	TP
48	209	W/P	Self-Test Input	STI
49	89	O	Heated Oxygen Sensor Ground	HO2S GND
50	967	LB/R	Mass Air Flow Sensor	MAF
52	562	LB	Injector 8	INJ 8
54	331	PK/Y	Wide Open Throttle A/C Cut-Off	WAC
56	395	GY/O	Profile Ignition Pick-Up	PIP
57	361	R	Vehicle Power	VPWR
58	555	T	Injector 1	INJ 1
59	556	W	Injector 2	INJ 2
60	570	BK/W	Power Ground	PWR GND

1994-1995

1	37	Y	Keep Alive Power	KAPWR
2	511	LG	Brake On/Off (AODE Only)	BOO
3	679	GY/BK	Vehicle Speed Sensor(+)	VSS+
4	648	W/PK	Ignition Diagnostic Monitor	IDM
5	970	DG/W	Turbine Shaft Speed Sensor	TSS
6	676	PK/O	Vehicle Speed Sensor (-)	VSS-
7	354	LG/R	Engine Coolant Temp. Sensor	ECT
8	238	DG/Y	Fuel Pump Monitor	FPM
9	968	T/LB	Mass Air Flow Sensor Return	MAF RTN
10	198	DG/O	A/C Cycling Switch	ACCS
11	101	GY/Y	Canister Purge Solenoid	CANP
12	560	LG/O	Injector 6	INJ 6
13	561	T/R	Injector 7	INJ 7
14	562	LB	Injector 8	INJ 8
15	559	T/BK	Injector 5	INJ 5
16	259	O/R	Ignition Ground	IGN GND
17	658	PK/LG	Self-Test Output/Malfunction Ind.	STO/MIL
18	914	T/O	Data (+)	DATA (+)
19	915	PK/LB	Data (-)	DATA (-)
20	57	BK	Case Ground	CASE GND
21	264	W/LB	Idle Air Control Solenoid	IAC
22	926	LB/O	Fuel Pump	FP
25	743	GY	Intake Air Temp. Sensor	IAT
26	351	BR/W	Reference Voltage	VREF
27	352	BR/LG	EGR Valve Position Sensor	EVP
30	199	LB/Y	Transmission Range Sensor	TR
31	190	W/O	Secondary Air Inj. Bypass Solenoid	AIRB
32	639	LG/P	High Fan Control	HFC
33	360	BR/PK	EGR Vacuum Regulator Solenoid	EVR
34	200	BR	Secondary Air Inj. Diverter Solenoid	AIRD
35	558	BR/LB	Injector 4	INJ 4
36	929	PK	Spark Output	SPOUT
37	361	R	Vehicle Power	VPWR
38	925	W/Y	Electronic Pressure Control	EPC
39	557	BR/Y	Injector 3	INJ 3
40	570	BK/W	Power Ground	PWR GND
41	224	T/W	Transmission Control Switch	TCS
42	883	PK/LB	A/C Pressure Switch	ACPSW
43	94	R/BK	Heated Oxygen Sensor - Left	HO2S-L
44	74	GY/LB	Heated Oxygen Sensor - Right	HO2S-R
46	359	GY/R	Signal Return	SIG RTN
47	355	GY/W	Throttle Position Sensor	TP
48	209	W/P	Self-Test Input	STI
49	923	O/BK	Transmission Fluid Temperature Sensor	TFT
50	967	LB/R	Mass Air Flow Sensor	MAF
51	237	O/Y	Shift Solenoid 1	SS1
52	315	P/O	Shift Solenoid 2	SS2
53	924	BR/O	Torque Converter Clutch	TCC
54	331	PK/Y	Wide Open Throttle A/C Cut-Off	WAC
55	228	DB	Low Fan Control	LFC
56	395	GY/O	Profile Ignition Pick-Up	PIP
57	361	R	Vehicle Power	VPWR
58	555	T	Injector 1	INJ 1
59	556	W	Injector 2	INJ 2
60	570	BK/W	Power Ground	PWR GND

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