2011 S80 throttle problem........

[Ratzend]

Hi,

I have a 2011 S80 D5 which runs fine.

Except for an intermittent potentially dangerous problem with the throttle. Occasionally there is no response at all from the accelerator.
There doesn't seem any pattern to it, hot or cold engine, hot or cold weather are the same.

A typical example is coming up to a T junction close to where I live, it is on a slight hill. You often have to wait for a gap in the traffic and when you get one you have nothing !!!
Pumping the pedal several times seems to bring it back but it can lead to some very dangerous situations. I have sort of grown used to being prepared for it but it still catches you out, sometimes at roundabouts, it also happens whilst the car is in motion, not necessarily pulling away from a standstill.

It was in for service at the local Volvo dealer on Anglesey a few weeks ago but they said they couldn't replicate the fault. I also pointed out an intermittant problem with the driver's seat belt not pulling out, but they couldn't fix that either.

Having done some research I discovered that the seat belt problem was a loose connection under the drivers seat, and had been the subject of a recall on several models.

They said they updated the car's software and it did feel as though the throttle problem was better but it is actually just the same as it was before. I took the car to Le Mans and we had several very dicey moments!!

Apologies for the long posting, I am not sure how to describe it properly?

Any comments would be appreciated, thanks,

Martin

[M-R-P]

Normally I'd complain about a new member coming straight-in with a problem but this is one that should have a bit of a priority.

Did the dealership run a diagnostic on the car? With such a new model, I would be extremely surprised if it didn't log some kind of code. The ECU is very picky and if a signal is missing (no response from the engine to match the pedal) it should throw a fit and store a DTC of some kind.

Pumping the pedal won't (I believe) make a difference, other than fixing a loose connection i.e. shaking it until the connection is made again. The throttle is completely electronic.

Welcome to the forum by the way

[stribo]

Did the dealer plug it into the VIDA diagnostic software? If so it should have shown up either a throttle body, or throttle pedal fault, unless the wiring's at fault, or one of the plugs has an iffy connection, but even so a fault should flag up.

[Ratzend]

My sincere apologies for just diving in with a problem, I realise that is not really appropriate behaviour.

Yes, they said that no codes were stored and even though it actually happened twice on the way to them they couldn't replicate the fault. They even kept it overnight so they could try it cold in the morning. I had hoped and assumed there would be fault codes.

They said that part of the service was to update the software on the car, and certainly something had been done as various user settings had reverted to default.

It has never got to the point where pumping the pumping the pedal hasn't brought it back. I realise it is electronic so not like pumping a carb, it just feels like it. At the point it fails, and there is no response, you can push the pedal right to the floor with no effect at all.

I am not planning to sell the car at the moment but I don't believe I could sell it if I wanted to with this sort of fault.
Plus, of course, it is dangerous!

[Ratzend]

Just as an additional point.....when it happens, the engine doesn't cut out, it just idles, and if it happens on the move there is just no power or acceleration.
The engine has never stalled.
I have never seen any lights on the dash or had any messages afterwards either.

Thanks,
Martin

[M-R-P]

Hmmm...

The D5 gets it's throttle control from fuel pressure iirc...

The wiring runs along the front of the engine...

I wonder if there's a dodgy connection along there somewhere? the FPS lives there too (it's where you plug a DTi tuning box if you were to fit one)

Sooner or later this fault has to throw a code. I'm thinking FPS, or sender, blocked filter, something simple.

[Ratzend]

Thanks, I will go around and remake as many connections as I can find. If only there were some sort of pattern to it I might have a clue, but it seems completely random, and can go for days without happening and 3 or 4 times on a single journey. Very frustrating, but it is weird that no fault is being recorded by the car.

[stribo]

It sounds like a wiring problem to me, might be an idea to check all the earth points are clean, and secure.

[Ratzend]

Thanks, I will check the earths too.

Although there is no real pattern it always seems to be pulling away from stationary. On rare occasions it has happened in motion, slowing down for a roundabout, when you accelerate into the roundabout there is nothing, until you have hit the pedal a couple of times. In general it is pulling away from a standstill.

[LeeT5]

If there are no fault codes logged (which the dealer said there wasn't) and they couldn't replicate the problem, then it sounds to me like it's not an electronic fault.

Can I ask how many miles your D5 has done?

Considering your symptoms and the fact there are no fault codes, I would suggest the fault lies with the actual throttle butterfly getting stuck in the closed position (especially on a diesel). It won't cause the engine to stall because it does not close 100%.
It's not uncommon for this to happen as I have seen it on many other makes and models. It also won't log any codes because the throttle potentiometer (foot pedal) is still working correctly.

Rather than start pulling your car apart in a fruitless search of an unknown fault, the mere fact your car is a dirty diesel, I would start by running a can of EGR cleaner through your intake. Its the simplest, easiest thing to do and can make a massive difference!

Cost is no more than £10 at any local parts shop and if anything, it will actually help rather than hinder! If it does nothing more than clean the throttle, EGR and various other components in the intake system including BPS and intake valves....then that's better than nothing at all.

You will need a 2nd party to sit in the car and hold the throttle at around 2000 - 2500rpm on a warm engine.
Remove the air filter or undo the cover as you need to spray the stuff directly into the intake. Do not spray onto or infront of the MAF sensor!!!

Then simply press the can nozzle for short 2 second bursts at 5 second intervals until the can is empty. Will take you about 10 minutes. The revs must be kept at 2000 - 2500rpm. They will go up and down during the process, but just make sure you only squirt the can when the revs come back down.

If the throttle was gummed up and sticking, then this will clean it all off. It will also clean your EGR valve and remove alot of the carbon build up in the throttle tract and intake.

Then test drive! If it doesn't work then you've lost nothing other than a few quid, your time (about 30 minutes) but you'll have gained a clean throttle body, EGR and the like.
Diving in head first when you don't even know what the fault is is pointless if you ask me. Not meaning to pick on Stribo (and I'm not having a go mate) but yes it might be an earth that's loose or dirty, however, if it were an earth you'd definately have more than one fault and do you actually know which earth point you need to check that's in direct association with the throttle pedal or ETM??
IIRC there are around 20-30 earth points all over the car....you gonna check, clean, undo and retighten them all?? I don't think so! Most of them are buried behind interior trim.
There are a few earth points that are easy to check under the bonnet but it is not common for these to come loose or become rusty, especially on a 2011 model.

[jamesy12345]

At the risk of getting flamed for saying 'I think'.....a while ago I had a focus diesel & the owners manual made much of the fact that the fancy fly-by-wire throttle returned to idle when the brake pedal was pressed.

Maybe worth a squirt of WD40 in the area of the brake pedal switch/checking your brake lights extinguish on release of the middle pedal

...just a thought...&....

[Ratzend]

Many thanks for all the suggestions. I will check the connections anyway as I have to find the one that causes the seat belt retraction problem, although I believe that is under the seat.

I have ordered some EGR spray as I am not near a motor factor and I will give it the treatment as you have suggested, as you say, I have nothing to lose.

The car has just turned 30,000 miles which is fairly low but faults can happen at any stage.

I will also give the pedals a spray of WD40, it is an automatic by the way. Other than this problem the car runs beautifully and I am very happy with it.

Thanks again for sharing your expertise.

[jamesy12345]

See below for what the brake pedal/light switch looks like

http://www.ebay.co.uk/itm/Volvo-S80-...#ht_1321wt_952

[M-R-P]

Out of interest - where's the throttle body on a D5? I couldn't find one on chavboy's 163.

Wow - that's not the sort of question I ask but seriously, I couldn't find a throttle. Is the new D5 that different?

[LeeT5]

Out of interest - where's the throttle body on a D5? I couldn't find one on chavboy's 163.

Wow - that's not the sort of question I ask but seriously, I couldn't find a throttle. Is the new D5 that different?

Errr...under the manifold/plenum chamber!

[M-R-P]

Errr...under the manifold/plenum chamber!

Actually under it - between the chamber and the head? I feel I'm missing something here the pipe from the EGR connects to the plenum on top of the engine and the throttle is actually under the plenum..?

That would explain why I couldn't find it lol.

[Ratzend]

God, I am getting old .................

I have just been reminded that I bought a DICE on an Ebay auction a year ago and it's never been out of the box!

I will find it and see for myself if there are any codes, and maybe leave it connected and go for a drive. It will be interesting to see if anything registers at all.

[Ratzend]

At the risk of getting flamed for saying 'I think'.....a while ago I had a focus diesel & the owners manual made much of the fact that the fancy fly-by-wire throttle returned to idle when the brake pedal was pressed.

Maybe worth a squirt of WD40 in the area of the brake pedal switch/checking your brake lights extinguish on release of the middle pedal

...just a thought...&....

That is very interesting, I wonder if the S80 works on the same principle. If there was even a very slight delay in the brake releasing then the throttle would be inoperative, and because it technically wasn't an actual fault, there would be no codes.........

I will try accelerating at the same time as braking tomorrow and see what happens, thanks.

[jamesy12345]

That is very interesting, I wonder if the S80 works on the same principle. If there was even a very slight delay in the brake releasing then the throttle would be inoperative, and because it technically wasn't an actual fault, there would be no codes.........

I will try accelerating at the same time as braking tomorrow and see what happens, thanks.

That was my thinking but equally I could be talking rubbish

edit

be careful!

[Ratzend]

Unfortunately it seems that you can accelerate and brake at the same time but I will give the WD40 a chance to work.