Engine Harness Connectors

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4AGE 20V Blacktop

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20V 'Blacktop' Project - Engine Harness Connectors

Here's the full list of all the connectors with wire colors and signal names (blue are signals that go to/from the ECU) where known:

Engine Harness - Body Harness Connectors

To Body Harness Denoted Plug 'A'	NC	NC			NC	Speed Sensor -> ABS light R/Blue
	Alternator Pin #3 Y	NC	NC	Water Temp Sensor -> Temp Gauge Y/G	Speed Sensor -> Speedo W/Blue	Speed Sensor -> Door Ajar? R/W
	NC	NC	ECU B Pin #13 'ELS4' (Defog Switch) -> Gauge Blk	Reverse Switch R/Blk	Oil Pressure -> Gauge W	Chassis Ground Brown

Red: To Speed Sensor

To Body Harness Denoted Plug 'B'	ECU C Pin #16 'CCo' (Exhaust Temp from Sensor) LG	Diagnosis 'CCo' LG	ECU C Pin #5 'W' (CEL) R/Y	Diagnosis 'W' R/Y	Ignitor Pin #2 Blk	Diagnosis 'IG-' Blk
	Alternator Pin #2 R/Blue	Reverse Switch R/Blue	NC	NC	NC	FB Grey7 #2 Blk/W
	Similar colored cells are shorted together

To Body Harness Denoted Plug 'C'	Diagnosis 'AB' Blk/Y*					ECU A Ref Brown	ECU C Pin #3 (Exhaust Temp) -> Gauge R
	NC	NC	ECU C Pin #9 'SP1' (Speed Sensor) -> Gauge Purp/W	ECU A Pin #7 'ELS3' -> Battery Gauge G	NC	NC	NC
	NC	NC	NC	NC	NC	NC	NC
	* NC on socket

To Body Harness Denoted Plug 'D'	Injector Ref -> IG Switch & EFI Fuse Blk/W	AC Compressor W/Blu			AC Compressor LG/Blk	Coil & Sensor near Coil -> IG Switch & EFI Fuse Blk/W
	Diagnosis 'T_S' Blu	AC Compressor Y/Blk	Alternator W		NC^	NC
	ECU C Pin #14 'FC' G/R	ECU A Pin #21 Blue/R			NC	Diagnosis 'FP' -> Circuit Opening Relay Blu/Blk
	Diagnosis 'T_C' Purple	ECU C Pin #1 '+B' -> C.O.R Blk*	ECU C Pin #10 'AC1' Y/R	ECU C Pin #21 'ACT' R/Blu	Diagnosis 'WA' -> ABS W/R	Diagnosis 'WB' -> ABS Y/G
	* Blk/R on socket			^ Blu/W on socket

Engine Harness - Junction Blocks Connectors

To JB1

	FB Grey Pin #1 W			FB Grey Pin #2 W
	FB O Pin #2 Blk/O	AC Fan #2 Blk/Y	NC	FB Grey Pin #3 Blk/R

To JB2

	WW Pump Blu/Y	WW Pump Pink*	Headlights R/Y	Unknown Conn W/G*	NC
	FB O G/R	FB O W		Unknown Conn LG/Blk*	NC
	AC MG Blu/R	AC MG Blu/Blk	Fog Lights R	NC	NC
	* NC on male connector on JB2

	L. Turn S G/Blk	NC				WW Pump Blu	FB BLK Pin #5 Blu/Y	Brake Fluid Level R/Y
	R. Turn S G/Y	R. Sidemarker G/Y	R HL R/G	NC	L. HL R/G	L. DRL G	R. DRL G	FB Grey Pin #5 R/W

ABS	NC	NC	ABS Relay Y/G					NC	NC
ABS	NC	NC	ABS Comp #18 Purp	ABS Comp #7 Blue	ABS Comp #19 R	ABS Comp #20 G	NC	NC	NC

ECU Connectors

ECU 'A'

NC

NC

IGF

Blu/Y

NE

Blk

G2

G

NC

G

HT

Pink

RSC

Blk/W

RSO

Blk/Blu

#2

Blk/R

#1

Y

Brown

Chassis Ground

Brown

NC

LG/Blk

G-

W

G1

R

NC

IGT

Y/G

Blu/R

W/Blu

NC

#4

Blk

#3

W

Brown

Blue: Ignitor
Red: Dizzy
Green: O2 Sensor
Yellow: Injectors
Purple: ISC

ECU 'B'	VC Y	PIM LG/R	THA Y/Blk	THW W	KNK Blk	OX W	NC	VF R/W
ECU 'B'	Brown	Blu/Blk	VTA LG	NC	Blk	TE2 G/W	TE1 Blu/W	VVT R

Blue: Intake Air Temp
Red: Check Connector
Green: Oil Switching Valve
Yellow: Water Temp Sensor
Purple: Knock Sensor
Black: O2 Sensor
Pink: MAP Sensor
White: MAP & TPS
Light Blue: TPS

ECU 'C'

R/W

NC

Exhaust Temp to Gauge

R

NC

Check Engine Light (W)

R/Y

NC

NC

NC

Speed from Gauge

Pu/W

AC1

Y/R

Blk/W

Blk

NC

Circuit Opening Relay (FC)

G/R

NC

Exhaust Temp from sensor (CCO)

LG

NC

NC

NC

NC

ACT

R/Blu

NC

Diagnosis Connector	F_P Blu/Blk	W R/Y	E₁ Brown	O_X1 W	AB Blk/Y	NC	NC	IG- Blk
	CC₀ LG	TE₁ Blu/W	TE₂ G/W		NC	T_C Pu	NC
	+B Blk	V_F1 R/W	NC	NC	T_S Blu	NC	NC	WA W/R	WB Y/G

Injectors	#1	#1 Y	Blk/W
	#2	#2 Blk/R	Blk/W
	#3	#3 W	Blk/W
	#4	#4 Blk	Blk/W

O2 Sensor	HT Pink	ECU C Pin #12 Blk	OX W	Chassis GND Brown
Alternator	Terminal B		-	-
	ALT Fuse W	BH 'D' Pin #2 W	-	-
	FB Grey7 Pin #1 W	BH Black Pin #7 R/Blu	BH Blue Pin #5 Y	-
Knock Sensor	ECU B Pin #5 KNK Blk	-	-	-
VSV for EVAP	ECU C Pin #12 Blk	ECU B Pin #10 Blu	-	-
Speed Sensor	R/Blu	R/W	W/Blu	-
Speed Sensor	To Body Harness 'Blue'
ISC	ECU A Pin #10 RSO Blk/Blu	ECU C Pin #12 Blk	ECU A Pin #9 RSC Blk/W	-
Starter	Battery + Terminal 30 Blk/R	-	-	-
Starter	FB White Pin #2 Terminal 50 Blk	-	-	-

Oil Switching Valve (VVT)	ECU C Pin #12 Blk	ECU A Pin #16 VVT R
Oil Pressure Sender Unit	BH Blue W	-

Intake Air Temp (IAT) Sensor

ECU B Pin #9

Brown

ECU B Pin #3

THA

Y/Blk

MAP Sensor

ECU B Pin #9

Brown

ECU B Pin #2

PIM

LG/R

ECU B Pin #1

VC

Y

Throttle Position Sensor (TPS)

ECU B Pin #1

VC

Y

ECU B Pin #11

VTA

LG

NC

ECU B Pin #9

Brown

Windshield Washer Pump	JB2 Blu/Y	JB2 Blu	JB2 Pink	-	-
Ignition Coil	BH 'D' Pin #4 Blk/W	Ignitor Pin #1 Blk/R	-	-	-
Sensor Near Coil	BH 'D' Pin #4 Blk/W	FB Grey7 Pin #4 W/Blk	-	-	-
Ignitor	Coil Pin #2 Blk/R	BH 'Black' Pin #5 Blk	GND Inj. Bundle Blk/W	ECU A Pin #20 IGT Y/G	ECU A Pin #3 IGF Blu/Y
Distributor	ECU A Pin #4 NE Blk	ECU A Pin #18 G1 R	ECU A Pin #5 G2 G	ECU A Pin #17 G- W	-
Water Temp Sensor	Chassis GND B	ECU B Pin #4 THW W	-	-	-
Water Temp Sender Gauge	BH Blue Pin #4 Y/G	-	-	-	-
Water Temp Switch	AC Pressure Sensor LG	-	-	-	-
Reverse Switch	BH Blue Pin #14 R/Blk	BH Black Pin #8 R/Blu	-	-	-

R. Headlight	JB2 R/Y	JB2 R/G	FB Grey R/Blu
L. Headlight		JB2 R/G	FB Grey R/Blu
R. Turn Signal	GND W/Blk	JB2 G/Y	-
L. Turn Signal	GND W/Blk	JB2 G/Blk
Daytime Running (DRL)	GND W/Blk	JB2 G	-
		JB2 G
Fog	GND W/Blk	JB2 R	-
		JB2 R
R. Sidemarker	GND W/Blk	JB2 G/Y	-
L. Sidemarker	GND W/Blk	JB2 G/Blk	-

Horns

(High & Low)

FB O Pin #5

Blk

R Radiator Fan

AC Fan #3

W

CDS Fuse

Blue/R

L Radiator Fan

GND

W/Blk

FB Blk Pin #7

Blk/R

AC Relay Box

AC Relay	CDS (3A)	AC MG			AC Fan #3			AC Fan # 2
	FB Blk Pin #2 Blu		FB O. Pin #3 Blk/W			AC Fan #2 W/R			AC Fan #3 W/R
	R. Rad Fan Blu/R		JB2 Blu/R			R Rad Fan W			FB Blk Pin #1 Blk/R
		JB2 Blu/Blk	NC	JB2 Blu/R	GND W/Blk	NC	To AC MG Blk/W	FB O Pin #7 Blu/Blk	GND W/Blk	JB1 & FB O Pin #4 Blk/Y

AC Pressure Sensor

Water Temp Switch

G

ECU A Pin #21

Blu/R

ECU A Pin #16

LG/Blk

AC Compressor Pin #2

Blk/Y

AC Compressor	NC	AC Pressure Sensor Blk/Y	BH 'D' Pin #2 W/Blue
AC Compressor	FB Grey7 Pin #3 Blue/Y	BH 'D' Pin #6 Y/Blk	BH 'D' Pin #3 LG/Blk

ABS

ABS Relay		Main Fuse Box. W Conn Pin #6 R	AC Fan #3 Relay W/Blk	ABS Modulator 2 Pin #2 Blu
ABS Relay		ABS Computer R/W	JB2 Conn Y/G	ABS Computer R/Blu
ABS Modulator Unit 1	ABS Computer G/Blk	ABS Computer G/Y	ABS Computer R/G	-
ABS Modulator Unit 1	ABS Computer G/W	ABS Computer Blk/W	ABS Computer Blu/R	-
ABS Modulator Unit 2	ABS Computer R/Blk	ABS Relay Pin #3 Blu	NC	-
ABS Modulator Unit 2	ABS Computer Blu/O	GND W/Blk	NC	-
ABS RF Wheel Sensor	ABS Computer W	ABS Computer Blk	-	-

ABS Computer

Modulator 1

G/W

Modulator 1

Blu/R

RF WS

Blk

NC

To JB1 Conn

Blk/Y

Modulator 2

R/Blk

JB2 Conn

Blu

NC

Modulator 2

Blu/O

NC

Modulator 1

R/G

Modulator 1

G/Blk

Modulator 1

G/Y

RF WS

W

ABS Relay

R/W

NC

ABS Relay

R/Blu

JB2 Conn

Purp

JB2 Conn

R

JB2 Conn

G

NC

Modulator 1

Blu/W

Engine Fuse Block Connectors

Grey7	Alternator W				BH Black Pin #12 Blk/W
Grey7	AC Compressor Blu/Y	Sensor Near Coil W/Blk	NC	ECU C Pin #7 W/Blk	ECU A Pin #22 W/Blue

Black8	AC Fan #2 Relay Blk/R			CDS Fuse Blu	NC
Black8	Orange #9 & GND W/Blk	JB2 Blu/Y	NC	Left Rad Fan Blk/R	NC

Orange	NC	JB1 Pin #2 Blk/O				AC MG Relay Blk/W
Orange	JB1 Pin #4 Blk/Y	To Horns Blk	JB2 Conn G/R	AC Fan #2 Relay Blu/R	JB2 Conn W	Black #4 & GND W/Blk

White	ECU A Pin #16 LG/Blk	Starter Blk	ECU C Pin #12 Blk
White	NC	ECU C Pin #1 R/W	NC

BlackL	ABS 50A Fuse W/R
BlackL	Main Fuse & Batt+ Blk	Alt 100A Fuse W	Alt 100A Fuse Blk

Grey6	JB1 Conn W			JB1 Conn W
Grey6	JB1 Conn Blk/R	R. Headlight R/Blu	JB2 Conn R/W	L. Headlight R/Blk

Blue2

ABS 50A Fuse

W

ABS 50A Fuse

W

WhiteABS	NC			NC
WhiteABS	NC	NC	NC	ABS Relay R

Fuse Block Connections

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Disclaimer: This web page in no way replaces the MR2 repair manual. Follow what it says before me. The purpose of this page is to give you a better pictorial description of what to do. I cannot be held responsible for any mishaps caused by this web page.