OBD1 FZJ80 93/94 O2 Sensor wiring color

[SKULLGRINDER]

Both my EWD and FSM make it unclear what color wires ( harness side ) match up with the colors on the OEM sensor side ( 4 wires; red,blue,white,gray) Nor can I find NTK literature designating each color wire on the sensor side for heater heater signal and ground. Can someone provide me a photo of a factory harness plug and the wires in each associated number pin out? I recently replaced my sensors with new OEM and relocated to my manifold and now have a code 21&28 something I haven’t had before. Anything helps thanks

 

[Fj80oregon]

Isn’t the pin out in the OEM EWD?

 

[SKULLGRINDER]

Isn’t the pin out in the OEM EWD?

correct pin out for harness side. I am trying to figure out what each color wire on the sensor side indicates so I can confirm my pin out is going to the correct male end

 

[jonheld]

 

[SKULLGRINDER]

View attachment 4164589
View attachment 4164591

appreciate this. this is how I have everything hooked up and yet still have 21&28 codes. Ive triple checked this now. Tested sensors both have good OHM

 

[jonheld]

appreciate this. this is how I have everything hooked up and yet still have 21&28 codes. Ive triple checked this now. Tested sensors both have good OHM

Verify that pins 1, 3, and 4 on both O2 sensors are getting to the proper pins on the ECU according to the schematic.
Verify that pin 2 on both sensors are getting +12.

Pull the 15 amp EFI MAIN fuse out of the relay box on the left fender and allow the ECU to reset and clear all codes. Takes about 5 or 10 minutes.

 

[SKULLGRINDER]

2 ( yellow red) 12V + [ battery power ]
1 ( gray) .007V - [ ground ]
3 (blue white) .75V [ heater circuit ]
4 ( black yellow) 1V [ heater circuit ]

 

[jonheld]

2 ( yellow red) 12V + [ battery power ]
1 ( gray) .007V - [ ground ]
3 (blue white) .75V [ heater circuit ]
4 ( black yellow) 1V [ heater circuit ]

You should be checking continuity from each O2 sensor to the pins on the ECU for pins 1, 3, and 4. Not voltage.
The idea is to make sure the correct pins from the O2 sensors are getting to the correct pins on the ECU according to the schematic. Checking voltage tells you nothing.

 

[MileHigh80Guy]

Here is my attempt explaining the layout in 3D from the ECU/Harness side.

Post in thread '1993-1994 OBD1 fzj80 o2 sensor'

Apr 13, 2026

89465-69115

Just to reaffirm, O2 issues, wiring issues all resolved with these O2 sensors and of course repinning/replaceing the harness side of the connector.
When repinning, pay attention to the pin outs! They are mirrored, so don't let your brain forget that. LOL

I had flipped 4 with 2 and was chasing a code 21 to my wits end, turns out my brain has flipped them. Drew some pictures for my self in crayon, here are the non-crayon notes for posterity.

ECU Side

NOTE the 2 Grooves on the corresponding plug to get orientation correct when looking into...

• MileHigh80Guy

• 

(1) HT - Orange or Gray (H8)	(2) B+ - Red/Yellow
(3) OX - Black or Blue/White(H8)	(4) OX+ - Yellow or Yellow/Black(H8)

Note the 2 positioning slots on the O2 clip compared the the image in the post above.

EDIT: this is from a site selling the OEM (89465-69115) O2 sensor, each manufacture uses different colors, sadly, they sometime use the same color for all 4. Your mileage may vary.

(1) HT - WHITE	(2) B+ - BROWN
(3) OX - BLUE	(4) OX+ - GRAY