yuca

My scan indicates a 17965-Charge Pressure Control:Positive Deviation,physically the car stutters at about 75mph and the dreaded three warning lights come on;I read in another forum that a malfunctioning diverter valve would be a cause for overboost.One of mine looks oily,I haven't check it yet but was wondering if any of you guys could confirm that a diverter valve could trigger a 17965.
Thanks

yuca

stupid question:are diverter valves the same than mechanical recirculating valves?

paulroad

oil is normal, malfunction at 75MPH would not happen. Diverts are active under pressure, ie..step on the gas..boost builds, get off the gas..the diverters---recirculating valves... open and the pressure is bled off to recirculate.

Check allroadfaq.com's engine link.. go to the 2.7T design study guide.

It could be your N75 valve as this actuates the system.

But the three lights are likely not part of this at all.

paulroad

It is also possible yo have a simplple boost leak. You should [ressure test the system. Instructions are also on allroadfaq.com

This is from another post on the s4 forum (code search)

"Something is not right with your boost. Try running a block 114 and 115 and compare your requested vs your actual boost. And the duty of the n75 valve [boost frequency valve].

Here is another link that explain what the vag-com blocks are [must be registered software to be able to log blocks]"

http://www.ross-tech.com/vag-com/m_blocks/

yuca

Thanks.One question, can the boost be checked with the car parked and just accelerating the engine?or the engine has to be under load i.e. car running

paulroad

not at all it has to be under load.