Does anyone know what the wirings on '03 Evo front oxygen sensor mean? There are 2 black wires, one white, and one blue. Which are the signal, heater, and the ground wires?

I am getting a P0135 CEL and I am looking to replace my front o2 sensor right now. Also, anyone knows if there is an aftermarket o2 sensor that is shorter than the OEM unit? Currently the front sensor is wedged pretty tightly to the a/c compressor unit (or whatever that block of metal on the left of the o2 sensor is ). So I am trying to find a shorter unit that won't hit the compressor block and also allow me to put it in without having me move the compressor unit or drop the o2 housing.

Thanks.

 

white is always the signal.

 

Are you sure you hav a front O2 sensor problem?