I have a 2000 Honda Civic with 37,000 miles - rarely driven. My engine light came on and I took it to a mechanic - she said it was the primary O2 sensor. The car was running fine so I delayed having it replaced because he wanted $300. About 2 weeks later the engine light went off and has stayed off. The car continues to run fine. Should I go back and have it checked again? Thanks

 

Nope, just keep driving it if it runs fine and your gas mileage is normal. When you do need to replace it, they cost about $50 any ANYBODY can replace their own O2 sensor

 

You should be fine but make sure you check your gas mileage like stated above. In your manuel it says that the engine light will stay on as long as something is keeping it on. But if you drive car for three separate driving sessions and nothing has triped the CEL then your engine light will go off. But the previous code will stay stored in the ecu's memory banm. And o2 sensors cost about $200 from honda. Just so your clear on the price. Mind you this is Genuine Honda parts, not the Tuesday special at Discount Auto Parts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote">You should be fine but make sure you check your gas mileage like stated above. In your manuel it says that the engine light will stay on as long as something is keeping it on. But if you drive car for three separate driving sessions and nothing has triped the CEL then your engine light will go off. But the previous code will stay stored in the ecu's memory banm. And o2 sensors cost about $200 from honda. Just so your clear on the price. Mind you this is Genuine Honda parts, not the Tuesday special at Discount Auto Parts.</TD></TR></TABLE>

this is true, they do cost a lot to get the OEM ****, but im running a bosch o2 sensor (2ndary, the one on the CAT) and i haven't had an issue...cost me 30 bucks maybe.
im willing to bet that the sensor is probably on its way out..eventually that light will come on again..id say just for the hell of it, go buy a new one and install it yourself..its right there by the exhaust manifold and should not be hard or take long to install.

 

Dont forget the o2 sensor socket

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote">Dont forget the o2 sensor socket </TD></TR></TABLE>
what he said^

 

Thanks - is there a "how to" somewhere that shows a blow by blow on how to replace the primary O2 sensor?

 

Yep!

Unplug the electrical connector from the O2 sensor to the main wiring harness.

Unscrew O2 sensor from exhaust manifold (spray with PB blaster or penetrating lube first, it can be quite tough sometimes).

Reverse order to install, you're done. It's really that easy