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3-wire O2 sensor - plug pinout?

2K views 3 replies 2 participants last post by  BigBabyLou 
#1 ·
The heated Bosch oxygen sensor I have has 3 wires, two are white, one is black.
What's the pinout of the sensor connector?

Thanks
Lou
 
#2 ·
Hello,

I have a wiring diagram for the 1989-1990 3.8L engine. It does not have the connector pinout, but I think the diagram may help, regardless.

With the wiring diagram, I think you can figure out which pin is which by matching up the connector and the sensor. My guess is the black wire is for ground (obviously); you would just have to check which white wire goes to the Grey/Yellow wire (main power), and which white wire goes to the Tan/Red wire (left side sensor) or Tan/Orange wire (right side sensor) (both connect to the Electronic Engine Control Module).

Post a reply or send me a Private Message if you want me to email you this diagram.
 
#3 ·
Thank you for the offer but I have the same wiring diagram (also without connector designation and pinouts) and although the wire colors that you provided match on the harness side, the sensor itself does not follow this code.

I don't have the engine harness to check the connector wire colors and pinout, that's why I'm asking for help here, I'm sure somebody has a detailed diagram from a service manual or maybe has harness laying around and can check.

Thanks
Lou
 
#4 ·
I am not sure if I have the wrong diagram or the wrong sensor but the diagram shows the sensor using the grey/yellow wire to feed the heating element (that's grounded through the jacket of the sensor) and the other two wires are for the voltage signal.

However, my sensor shows no resistance on any pin against ground (the jacket of the sensor). But the two wires measured between each other show approx. 5 ohms of resistance. That's the heating element, I gather. So the black wire must be the signal, then, with no ground wire.

The sensor part # is E97F-9F472-AA.

Is the diagram wrong? I wouldn't put it past Haynes, they disappointed me before.

Thanks
Lou
 
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