Re: Help, Anti pollution fault. by Hell Razor5543 » Mon Nov 21, 2016 1:31 pm. I have a C5 Mk1 (2.0l HDi), and she would pop up the anti pollution fault every so often. A friend wondered if the EGR valve had an issue, and suggested disconnecting the thin rubber pipe that goes from the valve to the metal pipe along the bulkhead (to see what