'03 p5, o2 sensor issues w/ header installed

[kiwee]

last week i went over a bump and my check engine light came on.
went to the dealership today and they said my o2 sensor is fried. they did a diagnostic and they are saying that the 2nd sensor is not giving a reading.......
back in sept. i picked up a ractive header and cat-back system.
the shop placed my o2 sensor at the top of my header (in the 1st bung) and the 2nd o2 sensor wire was extended and mounted by the cat (in the 2nd bung).
i have checked and re-checked the connections and everything is fine for the connections. i reset the ecu by disconnecting the negative battery terminal.
the light goes off, once i restart the car, it goes back on.
if i do need to replace the o2 sensor, what are my options? cost? where can i get one? (not the dealership)

anyone have any help to provide? thanks! <!--Signature-->

 

[KpaBap]

measure the voltage on the signal wire for the o2 (it is the blue IIRC), it should be oscillatiing around 0.45volts at idle, if you give it some throttle it should go up a bit and if you introduce a vacuum leak it should read a low voltage like 0.2 or less...

if it's not doing any of these things or is sluggish to respond then you will need to replace the o2 sensor. It would help tremendously to know the exact OBDII code.

 

[kiwee]

oh and i have noticed my idle is dipping at times to 500rpm and then settles back in at 750.

 

[Mike R]

I'd check out the wires that got extended.

 

[kiwee]

bump.
will the mechanical fix work on my problem?
just to confirm, the secondary bung, is the bung that i extended the wires for the o2 sensor to reach right?

 

[Lord_Zath]

if the idle's weird, it coiuld also be the connection to the EGR valve...