My 2005 Audi A4 tdi started playing up the other day with intermittent power loss black smoke from exhaust, sometimes grey, and kangerooing is the best way to describe how it drove with no power around 2-3000rpm. Sometimes the stability control lights up and wont respond to the switch? The MAF and MAP sensors have both been replaced but the problem remains. I have cleaned the dirty EGR valve and performed an ECU reset. Leads to suspect are a water build up in the battery plenum, unblocked drains and checked ECU out for water , ingress but all looks good. I am desperate anyone got any ideas?
You can try sticking a bag of silica gel on top of the ECU to dry it out, but there's probably water in the connectors. Have you tried scanning it with VCDS/VAG-COM?
Thanks for replying but I have now fixed it myself by fitting a blanking plate to the EGR valve plumbing, it looks as though the feedback potentiometer .inside the electric valve has packed in leaving the ECU no idea whether it is open or closed. Let this be a good tip to all diesel engined car owners, familiarise yourself with how to block off your EGR valve and make a blanking plate before you have trouble because when this valve fails the car become's almost un-driveable. Also carry the tools to do the job in an emergency (Allen-key on VAG motors) -it may save you hundreds of pounds some time in the near future, just take a look in these forums how much trouble they cause. A thin shim of metal 30mm square is enough possibly made from a coke can, slacken the exhaust gas flange and insert to enjoy trouble free motoring and forget buying a new valve at £300 a go -Why did'nt Audi make this valve fail closed? -----also don't believe any fault codes generated, I had loads, its usually bollocks.
*_This is good advice, ignore it at your peril if you will.*_
another good tip is to regularly check the battery plenum under the windscreen is draining properly, I found these vents blocked and full of water also that someone has not replaced one of the screws sealing my ECU box for some nefarious reason? what a way to bring the customers in Eh? There's one drain under the brake servo, another under the battery-battery removal required to clear.
Yeah it really is a good car when it goes properly, its just that with all that smart electronic stuff you would think it would recognise a true fault and report it to the ECU properly not generate multiple red herrings or senor faults that aren't really there leading to confusion and much wasted expense trying to fix what appears as a wandering gremlin. I have bought 2 of these cars one after the other so there tells a tale. Watch out for the stealership though many of whom are piratesfor your hard earned coin. Why is it so difficult to get a workshop manual for these machines today? is another complaint I have as I'm guessing many other motor enthusiasts complain of?
Its a bit of a pain for them where I take my existing Audi keeping up with all the diagnostic software and that stuff.. I hear they've just invested in a new laptop there;)...
VCDS is not expensive: I've had it for years now, free updates for a licenced version. Well within the reach of a garage, and it will run on a cheap laptop.
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As for manuals, ELSAWIN is commonly available on Ebay, or use the official ErWin manuals.
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