I have a 2003 Accord 2.4L 4 Cyl. I had a check engine light that said that the Air fuel ratio was bad or had a bad ground. I went under the car and it looks like the wires where pulled out of the plug that goes towards the engine. I have been trying to re-wire it see if it works. I have tried to find out where the 4 wires go. On the sensor there is 4 wires 2 Black, 1 Blue, 1 White. On the that goes to the engine the colors are Red, Red with a Yellow stripe, White with a Black stripe, and a Green. I am trying to put the wires back together but I dont want to short anything out.

 

Which side "pulled out" the O2 side or the engine side of the harness......also can we assume this is the primary O2 sensor (pre-cat)?

 

The O2 Side was pulled out the Black White and Blue wires. Yes it is the one Pre-Cat. I am assuming that it is the primary O2 sensor. According to autozone its a oxygen sensor and an air fuel ratio sensor combined. Around 175$ for a new one. Trying to check and see if this one will work before I order a new one. They didnt have any on hand that I could look at for the wiring.

 

Are there two blue wires or just one.....so far I've figured out where two of the four go.

The other two, I know the wire color at the ECU/PCM but I'm pretty sure that color doesn't go all the way to the actual O2.

 

Sorry for the delay in response. There are 2 Black wires 1 Blue and 1 White. Thanks for the help.

 

See the attached pic. for the Air Fuel Ratio sensor terminal view.

1: Male - Wht wire goes to Female Red/Yel (Sensor Ground (AFS -))
2: Male - Blu wire goes to Female Red (Sensor Output (AFS +))
3: Male - Blk wire goes to Female Grn (Heater Control (AFSHTC))
4: Male - Blk wire goes to Female Wht/Blk (A/F sensor control)

 

Sorry to resurrect this thread from the dead!
I am currently fixing up a 2003 Honda Accord 2.4L that has all sorts of problems after I was gifted it due to an alternator seizing... and this thread was just what I needed!
The upstream O2 sensor was de-pinned from my connector as well to the point the connector is nowhere to be found! Ugh.
So I put these wires together in a different way before I came across this post. I also noted that no fuses were blown in spite of this. Now, I'm curious as to why that would be?
I haven't started my vehicle since I came across your solution, redbull-1. But I would like to buy you lunch if this fixes the o2 code instead of me just resorting to buying the overpriced, $175 or so upstream sensor and related fuses.

I hope all is well almost exactly 11 years later! Thank you!