Boost pressure sensor?

[phil13]

Hello all,
had a pretty good run until now!! 2 days ago my engine service required message appeared, initially no side effects and the car drove fine. But after a while it went into limp mode, I pulled over, turned it off, waited 5 and started it up, no message, revved free so off I set, covered about another 15 mile and it went into limp again, I was half way up a steep hill doing 5-10 mph but then it cleared itself again and I got home ok. Next day in limp mode all the time. Took it to local garage who put their snap on reader on and it said MAF fault and Boost pressure sensor. Replaced MAF sensor and taken boost pressure switch from intercooler and cleaned it, didn't look very dirty at all. Put it back together and tried it. Here's what some one might help with is that if I start it up , and within a couple of seconds hold it at about 2.5. - 3k revs it revs freely above and runs fine, when you let it tick over after about 20-30 secs it puts up the message again and goes in to limp not allowing revs above 3k. I got a reader and still get boost pressure signal fault, can the sensor be tested or is there anything else that could cause this. I live in rural Cumbria so I'm an age from a proper Volvo garage. Any advice greatfully appreciated. Cheers Phil

[gmonag]

Get the codes read on VIDA. It really is the only way to get to the bottom of an issue like this. Snap-On scanners just won't cut it with a Volvo.

[phil13]

Thanks Greg,
I know that is the sensible option , the only main dealers near me are 25 -30 miles away , I don't think it would drive there well as there are too many big hills. Would probably need trailering, unless any one knows someone around here (western coast Lake District)with vida but I don't recall any independents that are closer than the main dealer. I just thought that someone may have had the same symptoms and point me in the right direction.
Cheers Phil

[Clan]

Originally Posted by phil13

Hello all,
had a pretty good run until now!! 2 days ago my engine service required message appeared, initially no side effects and the car drove fine. But after a while it went into limp mode, I pulled over, turned it off, waited 5 and started it up, no message, revved free so off I set, covered about another 15 mile and it went into limp again, I was half way up a steep hill doing 5-10 mph but then it cleared itself again and I got home ok. Next day in limp mode all the time. Took it to local garage who put their snap on reader on and it said MAF fault and Boost pressure sensor. Replaced MAF sensor and taken boost pressure switch from intercooler and cleaned it, didn't look very dirty at all. Put it back together and tried it. Here's what some one might help with is that if I start it up , and within a couple of seconds hold it at about 2.5. - 3k revs it revs freely above and runs fine, when you let it tick over after about 20-30 secs it puts up the message again and goes in to limp not allowing revs above 3k. I got a reader and still get boost pressure signal fault, can the sensor be tested or is there anything else that could cause this. I live in rural Cumbria so I'm an age from a proper Volvo garage. Any advice greatfully appreciated. Cheers Phil

You had a code for boost sensor . The Air Mass Meter is just a consequence of this . Put your old Air mass meter back on unless you bought a genuine volvo one .
The boost pressure sensors are playing up lately so change that . about £85 .
you could get an idea if it is faulty by comparing the readout of atmospheric pressure from the other two sensors connected to the ECM , they should all read just about the same with the ignition on .

[gmonag]

It doesn't have to be a faulty boost pressure sensor either. A faulty turbo or air charge pipe leak can produce a boost pressure faulty flow message.

Check for leaks in the air charge pipe, especially at the resonator (not sure what MY or engine you have). Also check the vacuum system for leaks and VNT actuator for movement (if it is vacuum operated).

[colinbos]

I agree with gmonag, I've had the same symptoms.

There are two seals top and bottom of your Resonator box, only a couple of pound to replace, they break and cause limp mode as you have.

You can replace the seals or replace with a specific resonator pipe and your good to go.

Read this thread. Posts 23 and 26 are what you're looking at.

https://www.volvoforums.org.uk/showt...=262086&page=3

[phil13]

Thanks all,
For information it is a 53 xc90 d5 with 108k on the clock. I will take a look tomorrow at the suggested areas. I'm guessing it is nothing major as it will achieve full revs, just as soon as it ticks over it comes into limp.
Many thanks Phil.

[volvo for ever]

sounds like t=map sensor on intercooler

[phil13]

Hi, I have removed the sensor from the intercooler , cleaned it and replaced . It ran ok for about a minute then returned to limp. Is there a way of electronically testing these units?
Cheers Phil

[gmonag]

Is there a way of electronically testing these units?

VIDA will display output.