Rear heated oxygen sensor?

[S14Techy]

I've got a 96' 240. The dude who owned it before me put an exhaust and just left some old ass oxygen sensor plugging the hole in the exhaust pipe. I've owned the car for almost a year, but the check engine light just now came on. Is it worth replacing this sensor if the car has been running this entire time without it?

[2.0civic]

yes....

[Krappy]

haha yeah.... you should...

[yudalicious]

check the code first to see what it is, either pull the ECU to check it, or, if you're lazy do what I do and go to autozone and have them use the scanner. i don't get your scenario, wheres is the sensor exactly, and is it even connected or is it just used as a plug?

[S14Techy]

Its the one in the rear, under the tranny. Its had one in there as a plug, but it hasnt been plugged into the wiring harness...

[green91]

If its post cat it only monitors catalytic converter efficiency and has very little to do with a/f