Limp mode woes
 

Hello to the Volvo community. I have a 2006 XC70, 96,000miles full Volvo service history, owned for a year of perfect driving. A month ago whilst driving on M4 to Wales the engine system service light & triangle appeared but ran ok. On way back from Wales, also on steady motorway cruising the cars message changed to soot filter full & went into limp mode.
Following day took to independent who diagnosed faulty DPF temp sensor & confirmed the soot content was within normal parameters.
Car then worked for 2 days (50miles) & to my horror the engine system message re-appeared closely followed by limp mode but no soot filter message. Took back to independent who said its now poss the egr valve & recommended changing the egr position sensor.
This time myself & a technician from work removed & cleaned entire egr assembly (now shiny & new) & wasn't too sooty, tested egr function & fitted new egr position sensor.
Unfortunately after driving for 5-10mins (this happens everytime) the car reaches running temperature & goes into limp mode. Plugged into Snapon diagnostics which showed egr working & the fault of MAF showed up again as always. Was told by indy that this is normal when "something in the intake system is wrong". Took off & blew MAF assembly to no avail.

Now desperate I come to you experts for guidance on weather this is the cause of a common problem elsewhere like a leaky pipe or such like.
Sorry for long thread but like to be thorough, many thanks Gez.

How embarrassing, the engine of course is the mighty 2.4 D5 Auto lump....

What codes did you get to indicate a faulty MAF? Alternatively, just tell us all the codes you got? I'm suspecting you may have a P0244 in there somewhere...

Does it go straight into limp mode if you thrash it?

Thanks for responses, I will put up the fault code on Monday when back at work(where car is). And no car only goes into limp mode when you put foot down at running temperature, when it's warming up it pulls like a train & sounds perfect. Also when in limp mode, if you put foot down there's a chugging mettalicy sort of sound down by the passenger football direction, possibly turbo related, not sure where turbo is......yet??

If you've had a choked up DPF but your EGR was fairly clean when you removed it there's a good chance you have a very common leaky intercooler, this will give you a MAF error and fill your DPF with soot.

Before you spend any more money on the car, check the intercooler for leaks / oily deposits (indicating a leak)

Changing the intercooler is a morning's work at most and brand new ones can be had for less than £90. Have a look at this thread - https://www.volvoforums.org.uk/showt...er+replacement

I would highly recommend removing the DPF and give it a thorough deep clean 'on the bench' But only do this after you have solved your MAF problem .... Have a look at this thread - https://www.volvoforums.org.uk/showt...DPF+deep+clean

Tumneruk this is exactly the sort of advice I was hoping for, most of the threads I've spent hours trawling through seem to lead to bad intercooler, leaks or turbo Westgate. I will b putting up on ramp next week & in a way I'm hoping it's a new ic or it's back to the drawing board.

If it's not the intercooler itself I'd still thoroughly check the rest of the intake system for leaks / split pipes.

Yup will do, Will b doing a smoke test as first poor of call & c if the ic turns into a smouldering bonfire......

Try the rubber pipe leading to the turbo. Under load it can collapse, pinching off the air intake temporarily.

& thanks Joe....Will pit a keen eye on that!!

Is it easy to check, not been round back of engine yet?, & does this sound like something that would happen only when hot (soft) I guess??

Right, so last night I performed a smoke test by connecting to the intake tract towards turbo, through intercooler & back up into inlet manifold.........& nothing at all, no leaks to spot. Had a good look at intercooler which is not bowed, cracked or leaking any oil so i'm now totally stumped. The 2 red codes I had were;
ECM-44B0 Have replaced position sensor & cleaned out egr valve.
ECM-135F signal too high Have performed smoke test, no leaks.

What next please?????

Longhouse21 the following codes were all found but not active:-
BCM-0100
BCM-0115
BCM-0148
CEM-1A61
CEM-1A62
CEM-DF17 CAN-H
CEM-E000
ECM-1100
ECM-44A0
ECM-44B0 (ALSO FOUND AT FAULT?) EGR POSITION SENSOR
ECM-5730
ECM-6662
ECM-6663
ECM-6665
ECM-7700
ECM-E000
SUM-0336
TCM-0A31
TCM-E000

I guess if these were all to become active I should scrap it??
Still runs beautifully till hot??

The majority of the codes when I've done a search appear to come back as communication errors between modules or possible CAN errors.
One link I've found seems to point to possible issues with connectors on the wiring loom
( https://www.volvoforums.org.uk/showthread.php?t=266079 )
so may be something to look at?
First thing would be to clear the codes if none are showing as active then recheck if a fault occurs or just periodically to see what returns.

No mention of checking the swirl flap operation or position data.....

Also, the checks done on the new EGR position sensor to confirm that it works, were the same tests done on the old one to confirm that it definitely didn't work?

cheshired 5, I don't think the position sensor was ever tested, it just came up with a fault code by the independent garage? We put power across it & it moved the egr a bit but not fully & presumed it was duff.......the more I think about it the more I think the egr itself, although cleaned immaculately, is at fault here, & when it gets hot it gets stuck (the motor that is). Is there a way of testing egr if off the car???? I don't want to buy a new egr & find nothings changed....getting desperate now. Should I take to main stealer for more accurate diagnosis???? Anyone in Bracknell/Guildford have Vida????

Will do & thanks!!

longhouse 21, I've found more info(vehicle parameters)
ECM-AIR MASS 38.4KG/H
ECM-AIR MASS DESIRED 273.9MG/S
ECM-AIR MASS/STROKE 364.7MG/S
ECM-BOOST PREASSURE ACTUATOR,PWM 73.84%
ECM-INTAKE AIR TEMP (MAF) 29.86'C
ECM-EGR VALVE 100%
ECM-EGR VALVE POSITION SENSOR 0.88%

I think the last 2 are the key here!!!

So after countless sleepless nights I've bitten the bullet & ordered a new egr valve in the hope my hot running issues along with fault code of egr signal issue will be gone for good. My question now is will I have to have the adaptions reset for the new ege valve & indeed the new egr position sensor???

For anyone reading this thread & have a similar problem.....in this case it turned out to be faulty egr valve & by that i mean bad solenoid/actuator & not coked up, I also removed the dpf which filled with soot as a result of egr being stuck open by a very useful firm in Horsham who heat the dpf up to regenerate it.