Intermittent "Engine Service Required"
 

Hi guys,

Recently I started having some problems with my S60 D5. The mileage is 140k miles and so far everything worked very smoothly.
Whenever I'm driving up the hill and I press gas pedal to the floor between 2500 and 3000 RPM I get "engine service required" message. I went to my friend who has Autel Maxidiag EU702 to pull out the codes and here is what I got:
ECM-1200 - Air temperature sensor Signal too high
ECM-1300 - Mass air flow (MAF) sensor Signal too high
ECM-2800 - Fuel pressure control valve Signal too low

When I'm driving on a flat road everything works great.

The car doesn't loose power even when the service message appears, there are no leaking turbo hoses, the intercooler works fine. The MAF looks clean and there are no problem with the injectors. I checked and cleaned the EGR valve and mixer, there is no black smoke and yet something isn't working properly.
I also checked the vacuum hoses, engine pads and there are no leaks from there either.

Anyone can recommend something? What might be causing limp mode?

My V70 D5 2003 did the same for a long time prior to the in tank fuel pump giving up which in the end prevented the engine from starting but apparently they can fail intermittantly for a long time before finally stopping altogether and this put it into limp mode when accelerating . Also had a long standing power loss problem ( which also caused limp mode ) which I still suspect was a second problem which was never diagnosed despite checking nearly everything as this continued for a while after changing the electric pump , it may well have been a bad electrical connector which after jiggling all the critical connectors and running the car with the maf unplugged for a few miles seems to have cleared itself . The car has had no major component /pipes/sensors replaced since new other than the pump , its on 141k miles now .

Thanks Bernard333 for your advice. What engine codes appeared in your car when you had your problems? I'll give a try with maf.
The interesting thing is that in my case it only and always happens when I'm driving up hill with gas pedal to the floor. There are no problems when I'm driving downhill or on the flat terrain.

Matt , fault codes were checked by two different people ( not me) and there were no fault codes which is strange as I got the message ' engine system service urgent' on the DIM . I was advised that the engine mounted mechanical injection pump sucks fuel through adequate for normal driving except for starting and high engine load situations such as accelerating hard when the electric pump is then switched in with a relay for a brief burst . I wired in an ammeter into the fuel pump to see when it was kicking in and found that its off most of the time for motorway cruising at low speeds but put your foot down or even starting a slight incline when you see the instantaneous fuel figure on the computer dropping and it kicks in straight away . This might not be your problem but worth keeping in mind . My Bosch pump was replaced with a Denso pump from an old Toyota , its been running for 28k miles with no problems .

Swirl Control Arm??
 

The only time I got that message on the DIM was when my swirl control arm broke.

After replacing it, it still regularly came disconnected and I would get the message again whenever I put a high load on the engine.

As far as I know the ' engine system service urgent' message can be triggered by a large number of different issues some of which will also trigger limp mode . With my problems I found that the limp mode could be switched out and engine back to normal just by switching off and restarting again but it took a bit of getting used to as it happened quite a few times when I was overtaking on a hill and had to drop back .

That's quite interesting. At what RPM usually your car went into limp mode? Mine appears at around 3500-4000 RPM and I know that's when the turbo governor opens the bypass for the fumes in turbo. So it might be something with my turbo but I'll have a look at the pump too.

I think that with the newer models the modified the swirl arm but I'll check that as well. Thanks

It's the same in my case. After restarting the engine everything works fine back again.

Limp mode came in on mine around the same revs but only when putting foot to the floor , just using 60 or 70% of the engine power would save it from going into limp mode . Have had the turbo off mine and couldnt find a problem with it , I also purchased a duff turbo off ebay to refurbish , the one used up to 2004 D5 163bhp engines is nice and simple and not much to go wrong , no wastegate and just a vacuum actuator for the variable nozzle whereas more recent D5s use a stepper motor and complicated electronics which I reckon in years to come will cost a fortune to repair when they go wrong , just one more reason why I am sticking with my old D5 .

Quick update. I've been to volvo dealer for diagnostic and I must say they're bunch of amateurs - thay said everything is fine...
There is only one useful thing from my visit at the dealers. Before I went to volvo I read the codes using Autel MaxiDiag EU702.

I had three codes with EU702:
1. ECM-1200 - Air temperature sensor Signal too high
2. ECM-1300 - Mass air flow (MAF) sensor Signal too high
3. ECM-2800 - Fuel pressure control valve Signal too low

At dealers the codes were:
1. ECM-1300
2. ECM-2800
3. ECM-6805 - which is boost pressure error, not ECM-1200

This means that MaxiDiag isn't very relaible diagnostic tool. And I was thinking about buying it.

I forgot that when I was cleaning the EGR valve couple weeks ago I disconnected the injection pump and I remember that I was trying to start the engine with the pump disconnected after resinstalling the EGR. This will rule out the ECM-2800 code which probably appeared then.

Like I mentioned I also checked the engine pads and all the vacuumlines and they're ok. I think I'm left only with two things which might be casuing limp mode in my car:
1. Turbo governor or VNT valve
2. Turbo

There is also possibility like Bernard333 mentioned of checking the fuel pump but I think this might not be the problem in my case.

Check the variable nozzle actuator using method described by GSMGuy in the diesel section . The variable nozzle mechanics inside the D5 turbo look fairly bullet proof to me . I am repairing a D5 turbo at the moment and the failure on it was due to oil seals and thrust bearing ( see photo I posted of the nozzle) , the vanes and mech look ok on mine and you could test this without stripping the turbo down . Also found the same on the good turbo I removed from my D5 and then refitted , it is making a slight whine but nothing near critical yet . I recently experienced a failed turbo on a Galaxy diesel and this was making a very loud whine for a long time prior to failure , still have to strip that one down but think its also a vnt .