C5 Depollution Blues

Post by **dirkzobb** » 16 Oct 2013, 17:52

Hi,
Had many XMs but new to 2005 C5 diesel - 2.2hdi - as a car it's nice to drive and I've sorted most of the quirks and glitches except for the dreaded 'Depollution System Fault'. Yellow light only comes on at idle/start-up - will go all day down the motorway with no show. Doesn't affect the performance at all. Fault code is P0402 then after a while adds P0400 then to top it all P1352 and the lovely yellow light Here's what I've tried/checked - vacuum valves for inlet butterflys both work OK as does the turbo valve (disconnected them and brought up expected faults). Thought the EGR may be stuck open so blanked it off - no difference, Changed the MAF - no difference. Does anyone know what the airflow g/s should be at idle? Mine's about 15.8 - 16.0 g/s. With engine stopped it still reads 1.52 g/s with both new MAF or old MAF - should it be zero? Can I zero it? Tried running with MAF disconnected - no effect on performance but new fault codes relating to air temp as you would expect but no P0402 - weird! It's driving me crazy - any help / suggestions appreciated.........