O2 sensor

Do you know what the exact code number the diagnostic test said it was? Are there any other codes besides that one? If you have a brand new O2 sensor and the same code keeps coming up, its probably NOT the O2 sensor, and instead could be anything from a small leak in your headers/downpipe to a bad Catalytic converter. I had code PO133 (O2 Sensor Slow Circuit Response Bank 1 Sensor 1) on my 2011 Jeep Liberty (V6) after getting a cylinder misfire on the left 3 cylinders. I replaced the O2 sensor but the code kept coming up after about 20-30 minutes of driving, just like you're experiencing. I ended up actually having a dead catalytic converter on my driver side and had to have both replaced (for free, thankfully, under the federal emissions warranty). So, what I'm saying is that you should please try to find out exactly what code it is that's giving the check engine light, and reply back here! It may be a bad ignition coil and/or spark plug that is causing un-ignited gasoline from that cylinder to be dumped into your cat, which is casing the O2 sensor to give you a code. Or, it could be something drastic like the O2 sensor AFTER your cat that's saying something's wrong, which would mean your catalytic converter is the culprit.

I had the code P0158, bank 2 sensor 2. My car is running fine and don’t notice any difference in gas mileage or performance! I should add that this problem occurred after driving through deep flood water! My car was smoking white out of the exhaust for a while afterwards and I soaked the air filter!

Thank you! This context helps a lot. The flood water could DEFINITELY be a factor in corroding the wiring for the O2 sensor, especially if it was submerged in the flood water for an extended period of time for water to seep in through any tiny electrical openings. Was the water high enough so that your Cat (and thus all the O2 sensors and wiring with it) was submerged for longer than like 30 seconds? Additionally, CODE PO158 is for the O2 sensor AFTER your cat. Could you confirm that your mechanic changed the POST-cat O2 sensor and not the PRE-cat O2 sensor? Would be good to rule that out before we get to the post- cat's wiring. Since the issue is with the O2 sensor AFTER your cat, you will probably NOT have any performance or gas mileage issues, thankfully! Still, drive for a bit until most of gas tank is empty, and see if you still get your normal mileage & performance. My Jeep's O2 sensor issue was BEFORE the cat; my code said my cat wasn't being "efficient" enough (since it was broken), so it essentially told my engine to "hey, you need to burn more gas" when it didn't need to, and I saw 20-30% reduced gas mileage. Thankfully though, that doesn't sound like your issue.

I’d say I drove it through approx 2 feet or more, deep of water for about 2 mins. The car never stalled, just sucked up some water I’m guessing since the air filter was soaked. I changed out the sensor myself being it was an easy fix, directly under my front bumper then again I’m no mechanic so I’m not sure if it was pre cat or post cat! I changed the sensor based on the length and look of the replacement sensors matching up and had a mechanic tell me it was the correct sensor I replaced. Just trying to get a better understand of what may be the problem or if I should take it to a shop. I don’t believe all the sensors were submerged but possible that my cat may have got a little wet!

Gotcha! Is white smoke still coming from the exhaust? Also, if the air filter was truly soaked, it most likely sucked in some water like you said. In turn, this would mean that a much lower amount of air was being delivered to your engine to mix with the fuel and burn it up properly, dumping more fuel (and possibly water) into your Cat. This could have been what threw off the spent exhaust gasses passing through your Cat (and thus passing over your O2 sensors), damaging the fine wiring and metals on the O2 sensors with the excess, unburnt fuel covering the sensors. I did some digging and a lot of people suggest checking your oil dipstick to see if any water is mixed in with your oil, and also changing the oil entirely too. Here are some additional threads that seem very similar situation to yours: 1) http://www.g20.net/forum/showthread.php?109941-Car-got-flooded-it-finally-turned-out- but-shoots-thick-white-smoke-from-exhaust and 2) http://www.944online.com/cgi- bin/yabb2/YaBB.pl?num=1429226245/8

Sorry, the #2 link above was copied incorrectly, here it is: http://www.944online.com/cgi-bin/yabb2/YaBB.pl?num=1429226245/8

Thanks for your help.. My car only blew out smoke which looked like water for about 15 mins! My air filter was completely soaked, I checked my oil immediately after the incident which it appeared to look fine. Also my hybrid was driving in battery mode through most of the water until the 4wd kicked the motor on. Going to check the fuses tomorrow and see if I have possible blew any.. If not going to dreadfully put it in the shop this weekend! I’ll keep this post updated in hopes to help others if this happens to them!

Some 02 sensors have a third wire that is used for the heater circuit. You may need to trace the wires to make sure all are active, and have the correct voltage present during operation...And, you must use a digital volt meter that will not affect the low voltage of the pcm itself. Be careful, Good luck.