they did exactly that,
but i knew th code beforehand so i was gonna call bs.
they called me and said "hey yeah, turns out its not the egr valve, there's actually another series of probles causing the CEL", and i told them i had the car scanned and that i new the code was p0401, and would have it fixed by my own family mecanic. They called me back 5 mins, later saying they rechecked and the egr was defective and that the labour and part was going to be free.
they said i have to change my center engine mount which is leaking, the air duct has cracks causing air pressure loss, and my ac and alternator belts need changing.
i new about the belts so thats fine, but the engine mount i have no way of knowing, they want to charge 195$ + tax.
and air duct(which by that they mean the hose which connects the MAF to the throttle body) ill just leave and replace with a CAI.