o2 sensor bad or what?

Ok two weeks ago i got my header and catback put on my 96 gs. My cousin drove it down to his shop and put it on real quick for me. When he got back i noticed the check engine light was on (this has never been on beofre). He said something about he had to mess with the wiring fromt he o2 sensor behind the cat.. now i dont know why he had to mess with the wire but he had them all cut and put back together with electrical tape.. he said there were two white and he might have hooked them up backwards. Well I was just messing with it. Theres two white, one black, and one grey. I switched the whites around and the check engine light is still staying on. Could the sensor of gone bad during the install? Do I have to reset the check light somewere?

I read on vfaq something about the ecu waiting like 20-30 minutes into a drive to flag the o2 sensor if its down. would it take that long for it to realize its back up? thanx

i just noticed i got at least two small leaks were the cat is weled to the catback.. will that mess with the o2 sensor?

If the ECU throws a code, solving the problem won't get rid of it right away. When you go to the mechanic, they fix the problem AND clear the code. You can either keep the white wires switched and drive until it goes out, or clear it and see if it keeps coming back.

Exhaust leaks aren't good but won't set a CEL.

helliviknow;
All of my knowledge/experience with DSM's is on 1st generation models. However, from what I understand of the workings on the O2 sensor and ECM fault readings, the light will only stay on if the fault is present. To word that a bit differently, the ECM does store all fault codes until it cleared, but the light does not stay on unless a fault condition is present and persistent.

I would first retrieve what ever code or codes are stored. I would then reset the unit (disconnect the battery for about 1-2 minutes), then drive or run the engine until the check engine light comes on, and recheck the fault code(s).

My understanding on the O2 sensor is that the ECM reads it in fault under two conditions

1) No signal
2) Signal does not change over x number of readings (I'm not sure of specifics).

Since all of this started when you had the header put on, and wires were cut, it kind of suggests something got shorted in the process. First step would be to reset the ECM though, to be sure.

Mark

yes...unplug the battery, i had check engine light probelms to, and even if you fix teh probs, you still will need to clear the codes. if you uplug the battery like 'MrZ' said for about 1 or 2 mins or even 5 just to make sure it was long enough, that should take care of it, if it comes back on, chanes are that soemthing else is wrong and you should get the codes checked out.