[Boilerman2]

I have a 99 Sl2 that the check engine light is on. checked it with a OSB2 hand held scanner and it came up i believe...P0404 and P1404, checked boook and refers to EGR valve prob. took erg valve off,cleaned carbon and reinstalled. cleared codes, drove maybe 2miles came back on with same codes. does this mean the valve should be replaced?. or is there something else i should be checking?. any help would be appreciated.
Thanks