XC90 2.5T limp mode at full throttle - Help needed Topic is solved

Dragoz001 · Post by **Dragoz001** » 11 Jan 2022, 10:11

Hi all, I need some help / advice from you expert guys!
I bought an XC90 MY04 2.5T Geartronic 6 months ago with 215000 Km.
(I previously owned a 2.4D with a manual gearbox a few years ago and I've always wanted to buy one again but with a petrol engine).
The car is in good condition and has been regularly maintained by professionals.
The first problem I noticed with the car was its fuel consumption. Impossible to go below 20 l/100Km (12 mpg) whereas with my BMW 330ci, same driver same use, I get 11 l/100Km (21 mpg).
I replaced the O2 sensors and cleaned the MAF sensor with no success on that.
A few months ago I noticed that the small vacuum pipe that goes from the intake manifold to the compressor bypass valve was unplugged from the bypass valve. I found it strange and I suspected that this had been done on purpose.
I plugged it back however. The mpg did not improve after that either.
After that here is what happened twice on the exact same circumstances: while gently driving on a highway, I kicked the throttle pedal to pass a car and then the engine went into limp mode. I stopped the car, turned off the engine, started it again and everything went well again.
At home I checked the car with VIDA and got no error code.
2 days ago, I thought of the unplugged vacuum pipe. I unplugged it again (and blocked it to prevent a vacuum leak).
I tried to reproduce the problem and kicked the throttle pedal several times: no problem.
I have no experience on turbocharged car so I really hope this will be an obvious symptom for some of you!
Can it be the control valve?
Many thanks in advance for your help!
Gilles

Dragoz001 · Post by **Dragoz001** » 28 Jan 2022, 08:34

Hi all,
And thanks to those who've read my message hoping to give me some help.
I would like to inform you that I decided to replace the TCV on the car.
The one on the car was not OEM, it was a blue device that looked more industrial than car stuff.
I decided to go OEM and ordered a Pierburg unit.
I installed it last weekend and here's the result:
I've driven about 180 km since then (about 40 km in the city and 140 on highway).
The average consumption is now 12.9 l/100Km (18.23 MPG) that I never could reach before.
I drove gently but also had to kick the throttle to pass cars. No limp mode so far.
So I hope this was the issue.
Regards to all. Gilles