The check engine light came on for the 2004 Elantra I drive, giving me an error code of P0038 and P0136, indicating the oxygen sensor (O2) Sensor was having some problems. It lists Bank 1 Sensor 2 as the position.
Stopped over at the local Advanced Auto Parts, which was air conditioned, thank goodness. Had them look up the part and they found this, a Bosch oxygen sensor for 63.99.
It was pretty easy to reach down from the hood to get to the oxygen sensor, but it seemed a little tight with the wrench. Actually, practically unmovable so I cranked up the car on jack stands outside on the parking area/road and crawled underneath. Loosened it up with a couple sprays of WD-40 and it came free just fine using a nice BIG wrench.
It looked pretty yucky, here’s a pic:
Then I put the new one in, all shiny and ready to go, with the slightest bit of anti-seize compound on the threads (pre-dressed by Bosch, thanks!). Sanded the metal terminals on the connector coming from the car due to some corrosion, and dabbed a little dialectic gel on them to prevent any corrosion in the future.
Set everything back in order on the car, reconnect battery, hood down, jack up, remove jack stands, jack down (sloooowly) and try it out!
So far so good, no check engine light after driving 9 miles, give it a few days before we really know if this fixed it or not!