Ok so I'm super new to this so bear with me. I purchased my daughter this car last year. The CEL light was on and it's the secondary oxygen sensor. I bought the sensor for my neighbor to replace for me but when he got down there he has found that the plug coming from the car is not there. Just 4 wires. A pink. A green. A black with white tracer. And a black with red tracer. I then purchased a universal plug off the Internet. It has A red. A black. A white. And a yellow. We couldn't find a diagram showing those colors so I went to a local scrap yard and bought 2. One of them has a red. A red with yellow. A white with black. And a green.
The other one has a white with red. A green with black. A black with yellow. And a black with white.
How do we figure out which wire coming from the car, to connect to which wire coming off of either of these 3 plugs.
I need to get this car fixed. We have been trying to figure it out since December. She needs to be able to pass emissions.

 

 

Yours is the EX, so unlike the dx/lx the cat is not the exhaust manifold. It is down stream a little further. The second O2 is still after the cat but under car, so maybe it got snagged on something (wire) and ripped off. I would go back to the pull it yard and get anything your car is missing from another 2001-2002 ex. I'd rather just plug in another oem O2 with connector into the oem wiring with matching connector. Maybe get the section of pipe with O2 in it even. Since its hard to get them in and out and it could just strip as you try to remove it. They usually don't sell the cat so that section is most likely cut off already. After its all back together (may need some welding) reset all codes with a 20 dollar obd2 code scanner. It may not be able to reset abs/srs lights. You will have to drive a couple days to know if your light pops back on. You could have a new autozone o2 installed and wired correctly to old wiring and still get a check engine light. I've had that happen. Something could be a little off with non oem wires/plugs/O2 sensors and the computer may not like it. As long as main O2 is ok you should drive around fine without low performance or mpg. The second is going to make sure the cat is functioning so it will make you fail echeck. If you reset it then convince echeck to run car on the rollers before light pops back on (and you still pass sniff test) you could maybe sneak through and be good for two years. Take the light bulb out if you hate seeing the cel glowing.

 

The downstream (ex layout) O2 plug is right above the front sway bar under the car. Both front and back have four wires and square plug connectors.

 

I am in Houston Texas so I have to have emissions testing or I'd remove the bulb and go on about the day lol. My question is how do we know which wire is power which is ground and which 2 are heater wires? Coming from the car we have pink green BLK/white and BLK/red. None of the plugs have those same colors.
The guess is the wires showing (pink green BLK/white BLK/red) is from the original manufacturer and the Honda plugs we have from scrap yard came from a diff manufacturer. We have checked a million wiring diagrams. Even the one local Honda dealership printed for us. None of them show the colors hanging from the car.