Check engine light after oil pressure switch replacement?

I've had a problem recently with oil leaking from my 5.0. I tried to determine where it was coming from, but I couldn't tell for sure.
I ended up taking it in to a shop today, they replaced the oil pressure switch and o-rings on the drain plugs. Cool, I thought, problem fixed. Well now I don't have any oil leaking anymore, but a new problem is happening. After about 5 minutes of running, the ''check engine" light comes on and stays on. If I turn the engine off and back on again, the light will go out for a few minutes and then come back on again.
The engine runs fine, the only difference I have noticed is that the oil pressure gauge reads much higher now. Would this cause the engine to throw a code?
I'm taking it back in tomorrow, I'm just wondering if anyone else has had this happen after changing the oil pressure switch.
Any ideas will be appreciated.
Thanks, Glen

Thanks for the replies, guys. I wasn't sure whether or not the oil pressure switch would be causing the "check engine" light or not. I did notice that the oil pressure gauge now reads between the A and L in N-O-R-M-A-L, it used to read between the N and O. I was wondering whether the change in oil pressure reading would cause the computer to throw a code or not. I know these are just idiot gauges, so I guess the difference doesn't really matter.
I am taking it back in today, so I'll be sure to let you know what happens for future reference.
Thanks again,
Glen

Just got a call back from the dealer. They said they ran the car for about an hour, and drove it around for a while, and couldn't get the check engine light to come on. Furthermore, they said it had no stored codes!
Now I'm really confused. Can the check engine light come on and not throw a code?
Glen

So I picked the car up yesterday afternoon, they drove it for about an hour trying to get the "check engine" light to come on like it had been doing, checked for codes, nothing. I took it over to a friends house to see if we could bring up a stored code, nothing. I drove it around for over an hour last night on surface streets and the freeway, but the "check engine" light never reappeared.
Since I've done everything I can think of to determine why the "check engine" light came on originally, I'm just going to keep an eye on it and hope for the best.
Thanks for all your help.
Glen