Wet 2003 Impala senors after huge water puddles?

My 2003 Chevy Imapala went over some large water puddles and shortly after a check engine light came out. My local auto store did a check and stated there is a possible problem with a senor.

If the senor got wet, could it even give the computer a good reading?

Would it probably give a totally different reading once it dries?

How about giving a little more info, what was the code #, it will be in a format like P1234. What is the mileage on the car and maintenence history, any symptoms like running rough or anything like that. Hard to tell what is going on with such a thin description.

It says P0420 and the car has about 100,000 or more miles, the maintenance history was a leaking radiator which was repaired and then just the normal just new breaks, new struts, and some small exhaust system work. The symptoms seem to the simply that the car is running completely normal, not stalling, running rough, or anything.

From what I can figure out, it’s a difference between the front and rear (of the catalytic converter) oxygen sensors…rather, not enough of a difference. If water interrupted the connection, it’s possible. Also, if it’s some kind of high-flow unit, that can throw those codes, too. Let everything dry out, have the code deleted from the computer, and see if it happens again. As long as it’s running OK, and doesn’t throw that code again, my guess is you’re OK.

Have the code cleared and drive on. The next time its at a real mechanic (corporate chain “car care” places don’t count) tell them about it and ask them to inspect the wiring harnesses for the O2 sensors - especially the downstream. If no obvious problems are found ask them to clean them up and treat with dialectric grease. Also ask them to inspect all of your splash guards & heat shields and stuff like that.

If you have the code cleared and then it comes back have them read again, find this post and reply to it to post an update. Post the specific code again - this is always necessary to get help. And questions about maintenance are not questions about repairs. They are about the basic “service schedule” stuff - spark plugs, wires, filters, fluids. Many people ignore these things and then become mystified when they have issues.