Rodeo just serviced

I just had my 2001 Rodeo ,4cyl. 120,600 miles serviced with timing belt, water pump, checked the cam position sensor (mechanic said it was good) and EGR cleaned. After all said and done with mechanic resetting the ECM to erase trouble codes, I get my check engine light back on after driving 5 miles. I call the repair shop back and the owner of the shop told me to drive it for a few days to see if the light will come back on, if it does the mechanic said it could be a bad EGR valve. Has anyone had this experience with an EGR valve going bad on their rodeo. My code is still the same ones with EGR and cam position sensor. I just don't want to replace every freakin parts to see which one is the culprit and having to change a good part when it is not the problem. Can anyone give me a suggestion as to what is going on.

You had the CPS code before and after the timing belt swap? Either the timing is off now or the CPS is bad.