Hi I'm new on here to try and get an answer to my problem. My 2010 1.6 hdi partner had a stuck/faulty egr valve. Replaced the valve. Still showing up two permeant codes. P0490 not enough egr and P1459 egr jammed open. How could it be stuck open and show not enough egr also. I took the new valve off again and it was in the closed position. Put it back on then Engine management light come on and van had no power. I cleared that intermittent code P0489 and van went sort of ok again. The van seems to be low in power all the time until you get up to about 60 mph. Has anyone any idea what's up with it.