Emmissions codes

[Loaded NightraiN]

Posted this in the T-Bird forum.. Thought i'd give it a try here to.. Hopefully someone can help me!!

Ok so I was getting code: P0430 Catalyst System Efficiency Below Threshold (Bank 2)

So I changed the passanger rear oxygen sensor... 7 miles down the road I get my light back on... I pull:

P0141 HO2S Heater Circuit Bank 1 Sensor 2.... The way i'm reading this its the other side??

Does anyone have any clue as to what might be the problem??
thanks!!

[lectra]

I don't think the P0420 code was the sensor, but the cat itself. The PCM figures the cat's going bad if the upstream oxygen sensor and the downstream oxygen sensor match more than they should. My guess is, based on the new code when you changed one oxygen sensor, is somehow you may have knocked the other sensor loose or something. Make sure it's plugged in like it should be. A P0420 code makes it seem like the sensor you pulled was working, but the cat wasn't. If the sensor wasn't working, I figure the PCM could tell that, as the voltage from it would be pinned on one of the power rails (probably ground), but instead it seemed to be varying a bit (characteristic to a bad CAT). It should read a somewhat middle range reading, but should be fairly steady. Clear your code and check the plugs to all your sensors, and see what comes back.

I think P0141 is referring to no activity detected on that sensor, so you may want to check the plugs.

By th way: check the plugs!