i have a '06 mazda 3 s gt with 63k with a check engin light. 2 codes one for the IAT (IAT circuit high input) and then sencond code 02 sensor (heated oxygen sensor H02S (RF) circuit no activity. can anyone tell me what could be the problem or where to start before i start spending alot of money?

 

Kind of a dumb question...but do you make sure you tighten the gas cap until it clicks every time? I'm not saying that's the problem, but I Am saying that I've seen a lot of mystery CELs that ended up being only that.

good luck!

 

"no activity" in regards to a o2 sensor, probably means you need a new one. that might be a good place to start....