Contour Enthusiasts Group Archives Forums General Troubleshooting O2 Sensor

Ok, my O2 sensor went bad, well, apparently. My CEL ligh came on, so I took it to auto zone, they said it was the bank 2 sensor. So I bought the replacement sensor, but I can't find out where the heck to put it!? Yes I did try a search. Also, it seems the car is running fine, i've put quite a few miles on it since this has happened. Could this be a glitch?

Did you reset PCM after code read? What was exact code, since there are 4 sensors, 2 in each bank.

BTW a search as follows returns 45 hits: O2 sensor>Problems>Subject Only>Any Date

Buch, you're in luck. Bank 2 is the front bank, which is much easier to get at than bank 1.

Now you just need to figure out if it's the top or bottom sensor that needs replacement. The OBDII scanner would tell you this.

Here's a hint: it goes on the front exhaust manifold, near the oil filter. There are 2 sensors there, one on either side of the cat.

and the code should tell me which of the two to replace?

Yes, as per FAQ section here:
http://www.contour.org/FAQ/FAQ.cgi?s=probs&display=checkengine

P0430 What side?

P0430 - Catalyst System Efficiency below Limit - Bank No 2.

That means the sensor after the cat in the front bank is showing insufficient change in O2 levels from the sensor above the cat. It could be mean either or both are bad. It could also mean that the connections on the lower one are loose.

-Lance

So I just check the connections, replace one of them (if needed) and if the CEL doesn't go off, replace the other one?