management light

[chubbs111]

hi guys and gals,not sure if this is coincidental,yesterday i took the egr valve off my 2003 clk270 cdi,cleaned it with brake and clutch cleaner then refitted it yesterday tea time,started the car and it seemed fine,went shopping today and the engine management light is on,is there anything i have to do after cleaning the agr,tried to get it in to my local indie but he can not look at it till tuesday,is there anything i can check or do please