A4 2.0 TDI 170 DPF Issues & Rough Idle

**VAG** · 17-07-2012,08:42 PM

Hi There Just Recently Bought A Audi A4 2.0 TDI 170 The DPF Light Has Come On A Few Times Before But After Taking On Motorway Has Gone Off Each Time But Yesterday I Did A 400 Mile Round Trip And Made Sure Near To End Of My Journey That I Kept The Revs High And Used Fifth Gear To Aid Passive Regeneration But To My Surprise The DPF Light Has Come On Again Today So Had To Take It On Motorway And Has Gone Off, Also Have Rough Idle Sometimes Which Makes The Car Shake (Just To Add I've Had The Egr Valve Replaced But Still The Same) Any Help Will Be Totally Appreciated
Thanks In Advance For All Replies

**VAG** · 21-07-2012,07:30 PM

Anyone Got Any Ideas As Just Had DPF Light On Again Had To Take On Motorway To Turn Off

**Guest 2** · 21-07-2012,07:41 PM

Get a fault code scan done - could be a broken sensor

**royster** · 23-07-2012,05:32 PM

Got this very same problem with my mates A3 170TDI. Ran vcds over it and it said implausible signal on the G450 sensor which is in the DPF. Changed out the sensor. Problem is still happening but we've been through checking to see if the timing belt is correctly aligned as it was only done just before he bought it, changed fuel filter, running it on expensive Shell Diesel and filtering it as it goes in to the tank.

However one trend we have found that it runs like a bag of nails more often when its been idling in heavy traffic on warm afternoons (25c+).

Moving on if you do a google search on audi 170TDI running lumpy brings up alot on this and my mate has come to the assumption that he'll have to put with it as its a highly tuned engine.