My light came on and I noticed that the car was idling really made when in neutral. I took it to Autozone for the free diagnostic check. They said it's the Heater O2 Sensor. I know where both sensors are located, just wanted to ask if anyone's has had this problem before and can confirm that all I need to do is to change out the sensors (if someone can suggest which one it probably is that would help too), or if the problem might be something else. I called a local automotive repair and they want to charge $90 buchs to run a full diagnostics and then $250 to replace just the top sensor if that's what comes up.

 

I don't think it matters but its a 97, 4 cyl, automatic. 1.6L

 

it should be just replacing it/them. i had the same code on my 95, but it was right after i did a clutch, and i found out afterwards, that i had pulled a wire out. if you know someone else with a 96-00 civ, switch them one at a time and see if it fixs it and then buy the one that is bad.

 

I had my Engine light come on in my '96 civic and received the message about --low catalyst efficiency in bank 1...p0420 code I think...

Anyway, Autozone told me it was the O2 sensor (s) but in actuallity it turned out to be either a plugged-over-time catalytic converter (170,000 miles) or the more probable cracked exhaust manifold attached to it. I replaced the manifold and subsequent converter for about $225 (a Dorman replacement unit ordered onlin, a non-California approved model) and the cleared the codes. The car runs great, the light is gone and the same old O2 sensors ar in the car.

Just food for thought.
Good luck
KR

 

Thanks for the advice. I went ahead and changed the one before the coverter (took all of 5 mins) and the light went off and the car is running a lot better now. I'm glad I picked the right one and I didn't pay over $300 to do it.