Had the same issue with my 2016 D5
cracked pipe from intercooler to turbo
dealer replaced 2 pipes and said it is common issue for early models 2016 , was fixed in later models
to much pressure since its a small engine with both turbo and supercharger , the PVC pipes just not handling the pressure and also have some oil after the turbo...
i hope it will not return . also on diesel it can damage the DPF
in general in the engine there are about 5 pipes like this, better to replace all , any leak of air cause reduced power
i wonder how common indeed this issue for 2015-2017
12/30/2019 So they fixed the issue by replacing all pipes? My 2016 XC90 T6 same code came up 2 days ago, 3 weeks prior to that I felt slight hesitation when gently touching gas pedal while moving over 30mph. I was under impression that one of the coils are going bad. But the code came up with the following possible issues.
Causes of the P0171 code may include:
A faulty fuel pressure regulator
A weak fuel pump
A clogged fuel filter
A faulty powertrain control module
A vacuum leak
Faulty injector(s)
Faulty oxygen sensor(s)
A faulty mass air flow sensor
I'm following process of elimination, cleaned MAS, now trying to find out where the Sweed's hid the fuel filter on new models (not where it used to be on previous model XC90) Anyone know where to look for it? Also replaced spark plugs while I was going at it, 3 of them look fine but one is darker, not burned, just look smoked more than the other 3.
Can anyone who went trough this rough patch confirm that your car is now fixed and what caused the issue?
Update: 12/31/2019 Still not finding the fuel filter to replace. Meanwhile cleaned MAS and took the car for a test drive, the car drove nicely, check engine disappeared after about 13 miles. At that point I was jumping dancing behind the wheel but then I felt hesitation when accelerating, that happen again driving few more miles then the hesitation was more frequent and then at total travel distance of 40 miles the hesitation is now permanent. The fumes from the exhaust pipes smell like gas/acetone - check engine did not return but I'm expecting it to appear very soon.
Next step: it looks like the MAS could be failing so I'm planning to pull MAS from my wife's 2019 XC60 to see if the car likes it, if it does then I'll know for sure that my XC90 needs new MAS. I will report once again.