Hello fellow civic owners,

I have a 05 honda civic lx 4dr. I recently bought an aftermarket exhaust with the proper placements for my two (2) o2 sensors. However, my engine light came on. I know it is because the second sensor is relaying bad oxygen messages to my ECU. I purchased an o2 simulator, but I do not know which o2 sensor to put it on. It tells me to put it on the rear sensor. Okay, so i go to the one after the cat, under the car, unhook it, and im ready. I notice that the wire colors do not match up according to the directions. Unfortunately the wires to the o2 sensor inside my headers, which I thought was my front sensor, does have the same color scheme as my o2 simulator. I am 100% certain that the actual sensors are in the right spot, meaning I didn't flip flop them when re-installing my new H/E. So, my question is: Which sensor is the rear and which senseor is the front because if the "rear" sensor is the one under or after the cat, then im %^&* because I don't know which wire(s) to splice.

A little more information is the o2 simulator has 2 wires: green and white.
My sensor going into my headers has 4 wires: 2 black, 1 white, 1 green.
My sensor underneath the vehicle has 4 wires: 2 white, 1 grey, 1 black.

My direction manual for the o2 simulator tells me to splice into the sensor with: 2 black, 1 white, 1 green.

I hope you can see my confusion and help me out.

Thanks!

 

just put it on one and if the CEL is still on put it on the other. if its not, leave it there. problem solved.