Racer's Lounge - Daily Driver Problem

I have an aftermarket MAF sensor on my 2002 Subaru wrx. I'm not sure what type of MAF is on the car. I purchased the car with the sensor already installed. I'm a member on one of the Subaru forums. I haven't heard anything yet.
Could this throw a cel of P0037 too?
If not the MAF, where is the sensor that is throwing this code? From what I found on research this would be the Air/fuel sensor and not the actual "O2 sensor". Where is the location of this part?
I know where one O2 sensor (blue, white, & black wires) is located but not the other. I'm not current with WRX exhaust. I lack knowledge of turbo exhaust systems.
Any help would get my car back on the road since the inspection tag ran out in October. Thanks!

if that's the only cel you're throwing it's for the heating element leading to the O2's. Specifically the two black wires that lead to the heating element in the rear O2 sensor. The element probably gave out.

I'd take it up to the dealership and have it looked at. Probably just need that rear O2 replaced.

Man this car is a pain. Fun to drive, but but not to work on. LoL, thanks for your input. Do you happen to know if the "rear" O2 is close to the turbo?

Man this car is a pain. Fun to drive, but but not to work on. LoL, thanks for your input. Do you happen to know if the "rear" O2 is close to the turbo?

lol no idea, this is the thread i got my info from.

http://www.clubwrx.net/forums/showthread.php?t=45821

the air/fuel sensor is the same thing as the oxygen sensor. For some reason some of the foreign cars like to use the different terminology