Mass Air flow Sensor XC90

[mev]

OK. sounds like good advise.
I will do a bit more investigation first although I am unsure as what to check next.
Even if VIDA says that the valves are opening can I be sure that they are all opening or causing a partial restriction.

[osullivant]

Originally Posted by mev

OK. sounds like good advise.
I will do a bit more investigation first although I am unsure as what to check next.
Even if VIDA says that the valves are opening can I be sure that they are all opening or causing a partial restriction.

Not sure if it can be established whether the valves are all moving, but if they are moving separately perhaps this would show as less air in a particular cylinder and perhaps this would show as less or more fuel used

But being realistic if the diagnostics say MAF, it just may well be the MAF which at €157 is a cheap fix for these cars.

To my mind if the MAF is changed and that fixes it then end of story, If fault remains with a known good maf and if yours works on another car then MAF is ruled out and you need to look further.

Have you cleaned out the throttle and the large pipe into the manifold. they fill up with crud.

Tony, my offer stands...

[cheshired5]

The MAF is reacting to engine speed and giving credible data which is basically saying that it's fine and to leave it well alone.

The precise wording of the code is important too.
A MAF sensor related fault code doesn't necessarily mean a faulty MAF sensor.

[osullivant]

Originally Posted by cheshired5

The MAF is reacting to engine speed and giving credible data which is basically saying that it's fine and to leave it well alone.

The precise wording of the code is important too.
A MAF sensor related fault code doesn't necessarily mean a faulty MAF sensor.

True but sometimes a cigar is a cigar, if it is easy to rule it out then this should be explored...

I have this tee shirt....

[mev]

No I haven't checked the throttle or manifold pipe but will do tomorrow. Thanks for that.

I agree that changing the MAF sensor is the easy option but I feel that there is something wrong with the swirl throttle valve and it needs to be checked/replaced.

I also have fault codes for "swirl actuator control offset fault ECM-18AO" and "heated oxygen sensor ECM-28DO, ECM-28EO" but I do not notice any change in engine operation when these come nor do I get an "Engine System Service Required" dash fault code. These are more random unlike the MAF sensor fault. I do not know how long they have been coming as I only plugged the code reader in for the first time a couple of weeks ago.

I have ordered a swirl throttle valve replacement kit (Volvo parts) online and hopefully this will sort my "Engine System Service Required" problem once fitted.

[mev]

I have had the swirl throttle valves replaced and the responsiveness and smoothness of acceleration was immediately noticeable.
The "Engine System Service Required" message has gone along with all the other codes including the MAF sensor code.
There was a lot of play on the old swirl throttle arm between where the actuator/motor link rod joins to the swirl throttle arm and the swirl throttle arm itself. So much so that I think the swirl throttle arm was not rotating at all.
Many thanks to those who posted replies and gudied me along the way.
Mev.

[osullivant]

Originally Posted by mev

I have had the swirl throttle valves replaced
Mev.

Well done on the fix.

How much did this job cost you? Did you have any injector issues!

[mev]

€75 labour by my local mechanic and €211 for the throttle valve replacement kit (Volvo parts) on ebay.
The mechanic had no issues with the injectors as the pipe work came loose without difficulty. It would have been a different story if any of them were seized as my mechanic was not in a position to deal with that outcome and I would have had to go elsewhere.
My local volvo dealer quoted me €400 for labour.

[Pudis]

Originally Posted by mev

Hi there,
I have a 2008 XC90 185bhp 2.4 D5 diesel.
While accelerating when the engine is warming up there is a loss of power for a second or two and the "engine system service required" masseage is displayed. This can happen several times during warm up.
I plugged in and the code for this is ECM-135F Mass Air Flow (MAF) Sensor.
I have removed the MAF sensor and visually it looks fine, electrical connections are good and I did not find any leaks in the pipe work. I have changed the air filter.
The measurements from the MAF sensor are 50kg/h at 700rpm, 60kg/h at 1025rpm, 90kg/h at 1500rpm and 130kg/h at 2000rpm.
It seems to be pointing to a new MAF sensor but before I get one I wanted to run it by you guys as a new MAF sensor from my Volvo dealer is a whooping €505.
My questions are:
1. Can I drive with the MAF sensor disconnected without damaging the engine and only expect to have lower mpg.
2. Can I clean the MAF sensor with a MAF sensor cleaning spray as from reading other threads some people are for it and some are against.
3. Could there be other things that I need to check before getting a new MAF sensor.
4. Could it be some other problem entirely and I am heading in the wrong direction with the MAF sensor.

All comments are appreciated.

Hello

I got the same ECM 135F code every now an then... (Volvo XC90 -08 D5 185hp)
Cleaned the MAF --> Did not help.
Cleaned the boost pressure sensor --> did not help
Checked the swirl arm --> was ok at the time, but i have been driving without the arm also and never got a fault code because of that?

When checked the IC and hose/tubes for leaks i found a damaged seal on turbo air resonator box...

Seal at the turbo end looked out exactly like in this thread.

https://www.volvoforums.org.uk/showthread.php?t=213256