The woe continues
 

Okay so,
I have had my S40 (2008 2.0 diesel Lux) for 18 months, a few problems along the way, but I love my Volvo.
About a couple of months ago I noticed an occasional and slight surging in power when accelerating hard in fifth and sixth.
It became worse, I changed the fuel filter...I had noticed air in the clear fuel line and thought it might be the cause. It seemed to cure it, so I thought that I would fit the spare cone air filter I had lying around. Fitted okay and tried it out, I heard a lot of unpleasant induction noise and the performance seemed sluggish and dull. I returned the intake to original but the performance didn’t really come back.
I obviously checked the intake system but found no problem.

The car went into limp mode showing an underboost code.
I cleared the code and it didn’t return.
However it feels like the engine is not producing boost. I bought a WiFi obd2 interface to use with torque pro, but it only worked a couple of times...much to my annoyance, so I haven’t been able to check the boost conclusively.

This is where the sore head begins.
I will condense the story, but suffice to say, that I have trawled through almost every thread on every forum trying to find a solution.
I have changed the inter cooler, visually checked the entire pressurised and vacuum sides of the engine system.
I have replaced the vacuum solenoids.
Replaced the MAP and MAF sensors.
Checked the throttle position sensor.
Used two treatments for sticking turbo vanes.

Its a lot of info, but hopefully someone can make some suggestions.
As I said initially, I know that there are other posts about very similar problems, but not many solutions.

Thanks for any help.

Hi Mate

Sorry I can't help directly as I don't have experience with that engine, but I think the best thing you can do would be to get a diagnostic scan with VIDA - the proper Volvo diagnostic tool. It's reasonably priced from eBay or sellers on here. You might even be able to find a local member who can help.

Even if there isn't a fault logged, VIDA has the ability to graph parameters as you drive - so you can spot things yourself.

ok this may or not help only just passed this onto a member on another forum but this cheap tool was able to read the map/maf pressure on a x type jag/ mazda/vauxhall so no idea on a volvo , but was able to find on the x type 2.0D that the actuator was sticking due to sticking vains giving low readings on the map sensor .
do a search though as there are cheaper outlets
https://www.ebay.co.uk/itm/D900-Car-...0AAOSwqT9cigBZ
another tool that works well on most cars is delphi /autocom if you have a spare laptop running winxp laying around or higher, delphi has so far done just about everything i have ever needed on many makers cars inc coding injectors /dpf regen and more cost is about £30-35 , just done a regen and eloys reset on my v50 1.6D

thanks for the replies guys.

I appreciate it.

i am surprised that this fault hasnt been stickied in the forum, it seems so common, but few have given an explanation or solution.

I have already contacted someone on the forum about VIDA.
rxtian thanks for the info about it, my concern was that i would buy VIDA at £100 odd, and it wouldnt give me enough info to find the fault.
i will look into the Delphi option again.

cheers.