Service engine light on ,on 2003 volvo S60

I have a 2003 S60 volvo i took it to the my mechanic for 105,00 timing belt change recommended by service manual he found that map sensor was missing so i had him to replace it and he said that the service engine light would go off because that was the reason it was on in the first place well the lights still on did anybody out there go though this the timing belt and map sensor cost me 1100 already

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

The CEL may require a few driving cycles (getting up to full operating temperature) before it will turn out the light.  It also could be related to something unrelated to the work you had done.

agreed, get the codes read and see what they tell you