Here is a link to a past thread dealing with code P2238. There are at least a couple other threads dealing with this code, so you'll want to use the forum's search feature and locate those threads as well. :thumbsup:
I have had the same thing with my 04 Camry LE I4. It will come on randomly, then i will try to get the code and the M.I.L will shut off. I do have Poor Idle and Gas Mileage(about 290 to 320 miles on full tank). I was told it was O2 Sensor on Bank 1 Sensor 1. I just want to figure out what it is so i don't have to spend 150 on an O2 Sensor and it doesn't fix it.
after going through and replacing the spark plugs, O2 Sensor, Cleaning the MAF, and some fuel system cleaning solution to the tank it never changed anything. i don't have the MIL on anymore but had the rough idle still. It turns out my PCV Valve was shot, so i replaced it and didn't do anything. I just took it in a few days ago to a shop and had them clean the entire air intake. When the PCV Valve stopped working it caused Oil to end up in my air filter and all over the intake manifold. So about the MIL, change the O2 Sensor, and if you still have a rough idle then check and see if your intake is caked in oil and dirt. Replace the PCV Valve and have the intake manifold, and throttle body cleaned. Toyotas in general are known for having this problem. also when you clean it out check your Throttle Position Sensor (TSP) and make sure it is not failing either. Mine has cleared up, but my friends same camry just had the P2238 Code at 151,239. Same rough idle problem.