I have an automatic 99 Prelude Base model.

So, I had my headers replaced the other week.. Everything fit. & There was a spot for the front O2 Sensor to be placed to plug in. Once done, the car ran beautifully. Than all of a sudden I get the check engine light on & what is it? The front O2 Sensor.

Now, I've heard that if you get new headers your O2 sensor is gonna throw a code until I program the computer to read that there's different headers on my car.

I don't want to pay someone to re-program my computer. & I don't want to waste money on a new O2 Sensor if it's not needed. The second O2 sensor isn't throwing a code..

What do I do?

 

In this case don't listen to what you heard.

Make sure that the O2 sensor is in tight, that the new header isn't leaking from somewhere upstream, make sure the O2 sensor wiring was not damaged in the header install and that it's plugged in, and lastly, after all that, try resetting the ECU to clear the code and see if it comes back.

 

you can also try puttin a spacer on the o2 sensor that goes the headers if resetting the codes doesnt work.

 

You don't need to program anything, the 02 is probably loose or is not connected.

 

thanks. it turns out it was fried anyway so i wound up buying one from ngk for 54.00. we'll see how this one works..

 

My 98 prelude auto is throwing a p420 cel at me for the very same reason except i have no aftermarket headers just high flow cat...my O2 sensor must be fried, or so many of my friends say...let me know if that ngk o2 sensor is working well for you....i need to replace mine, and $54 like you said isn't that expensive

I heard that a fried O2 sensor will harm gas mileage???? ...I get on average like 220 miles on a full tank...others i heard get like 350...so something is up

 

yea i recently bought a 99 prelude for my first car lol and my engine light is on too and im thinking its the o2 sensor. because of it tho ive been getting a lot of carbon particles and crap showing up on the back of my car cuz its metallic white. ive heard that a faulty sensor makes ur fuel run rich which wastes fuel and causes a lot of build up. and im getting around 220 to 225 mpg on a full tank now too. im new to all this so does ne one know where i can get a secondary 02 sensor for cheap? i found a four wire heated one for like 95 bux but im not sure if i need all that for my car to run well.

 

http://www.sparkplugs.com my friends for o2 sensors.