Engine: D5: Soot Filter driving me crazy...HELP !

[Bill_56]

Originally Posted by cornclose

Same issue here. Brand new V70 D4, collected it less than two weeks ago, within a week I get the 'Check Engine' amber lamp after about 480 miles.

Took it to the dealer the next day, they tell me the DPF Pressure Sensor has failed and a new one is required (they can't reset the codes to extinguish the lamp..). New one is on order and is due to land on Thursday this week, when the car is booked in to have it replaced.

Now, when they told me what the issue was, I asked them various questions about how the car will perform a regen with the failed pressure sensor. Will it do one based on time/miles/engine run-time etc ? It all fell on deaf ears and they don't have a clue, but they did say I can drive the car with no problems.

Fair enough.

Tonight on the way home, I get the message 'Soot Filter Full, see manual'. This is about 500 miles after the initial CEL came on. So it looks like it hasn't been doing any regens, and I've not noticed it doing one so am pretty sure it hasn't. Not that I know on this car how it would perform/sound though (on my previous car, an Alfa 159 JTDm, it was fairly obvious..).

My total mileage now ? Just over 1,050 - all my trips are 50 mins to 1:20 mins and are 50% motorway and 50% fast A/B roads. So there absolutely no reason why a regen can't take place. Never had a single problem with the Alfa in 94,000 miles, and I get this crap less than a week into ownership of the D4.

The drive is great, but this has pee'd me off no end...

If the pressure sensor has failed then, no matter how often the car successfully regenerates, it will always thinks it needs to regenerate again. It doesn't imply that regeneration is failing. So I'd say the diagnosis sounds correct, and that all will be well with a new sensor.

But given the alarming (if harmless) symptoms, I'm surprised they didn't offer you a loan car while awaiting the new part? I think I'd have asked for that, having coughed up for a brand new car...

[Clan]

Originally Posted by cornclose

Same issue here. Brand new V70 D4, collected it less than two weeks ago, within a week I get the 'Check Engine' amber lamp after about 480 miles.

Took it to the dealer the next day, they tell me the DPF Pressure Sensor has failed and a new one is required (they can't reset the codes to extinguish the lamp..). New one is on order and is due to land on Thursday this week, when the car is booked in to have it replaced.

Now, when they told me what the issue was, I asked them various questions about how the car will perform a regen with the failed pressure sensor. Will it do one based on time/miles/engine run-time etc ? It all fell on deaf ears and they don't have a clue, but they did say I can drive the car with no problems.

Fair enough.

Tonight on the way home, I get the message 'Soot Filter Full, see manual'. This is about 500 miles after the initial CEL came on. So it looks like it hasn't been doing any regens, and I've not noticed it doing one so am pretty sure it hasn't. Not that I know on this car how it would perform/sound though (on my previous car, an Alfa 159 JTDm, it was fairly obvious..).

My total mileage now ? Just over 1,050 - all my trips are 50 mins to 1:20 mins and are 50% motorway and 50% fast A/B roads. So there absolutely no reason why a regen can't take place. Never had a single problem with the Alfa in 94,000 miles, and I get this crap less than a week into ownership of the D4.

The drive is great, but this has pee'd me off no end...

The system relies on the pressure reading from the sensor to do regeneration , with no reading it will not regenerate hence your blocked filter .
Is this a 4 cylinder or 5 ? Never heard of this problem if it is the 4 cylinder .
They should have lent you a car . Lets hope they can recover the particle filter .

[Bill_56]

Originally Posted by Clan

The system reies on the pressure reading from the sensor to do regeneration , with no reading it will not regenerate hence your blocked filter .

I was deducing that the sensor had failed in such a way as to permanently cry wolf, demanding regeneration, as opposed to permanently quiescent. Otherwise, why would the car be displaying 'Soot filter full'? Doesn't that imply that the sensor is (incorrectly, here) continuously asking for regeneration, and that whilst the engine software reacts accordingly, it will never be enough?

That would probably imply less risk of DPF damage while awaiting the part but I'd still want a loan car, it can't be good if it is continually regenerating. Wonder what is happening to engine oil level, for instance?!

[Clan]

Originally Posted by Bill_56

I was deducing that the sensor had failed in such a way as to permanently cry wolf, demanding regeneration, as opposed to permanently quiescent. Otherwise, why would the car be displaying 'Soot filter full'? Doesn't that imply that the sensor is (incorrectly, here) continuously asking for regeneration, and that whilst the engine software reacts accordingly, it will never be enough?

That would probably imply less risk of DPF damage while awaiting the part but I'd still want a loan car, it can't be good if it is continually regenerating. Wonder what is happening to engine oil level, for instance?!

without knowing what the pressure is reading its hard to guess , but there are other mathamatical calculations which go on . It knows how much soot is being generated and going by distance travelled and engine behavior it can work out how much soot is accumulating when there is no pressure reading . If the pressure sensor was demanding regeneration all the time the ECU would use it's intelligence to know it was unreal .

[cornclose]

Originally Posted by cornclose

According to the manual, the 'Soot Filter Full' message means the particle filter is at 80% capacity, and to clear the message you need to drive the car for 20 minutes on main roads. Well, I do that twice a day at the very least, in two 1 hour runs.

Well it was driven this morning for 1:10 hrs over a 45 mile journey - message hasn't gone away. It was driven back again for another hour, at a much higher speed as the roads were clear (it was much later) - message hasn't gone away. So it's either as a direct result of the failed pressure sensor and it just 'thinks' the DPF is 80% full, or it really isn't doing any regens and that's why the warning is there still.

As said before, I'd have thought the regens would still take place at timed intervals (based on engine run time/driving style) without relying on the pressure sensor if it's not working, and maybe that's the case.

At best, the car is giving me misleading info. At worst, the DPF is slowly bunging up!

[pqpq]

If it's any help, my V70 D5 (2007) has been giving me similar problems.

However the symptoms were a little different. I was getting almost constant regenerations, but there would be a gap between each one, sometimes a few minutes, sometimes longer. Any strain on the engine would start a regen. Each time it was in limp mode, but went back to normal when the regen finished.

I know the regenerations were happening because the inside of the DPF filter was clean, and it's been doing this for 1000s of miles - if there were no regens in such a long period, I'd have much bigger problems.

The oil pressure sensor was changed today and I'm pretty sure the problem is now solved, although I haven't yet done enough miles with the new sensor for the computer to figure out that the sensor has been changed.

[cornclose]

It was the DPF temperature sensor that was faulty..

Yes, I had previously been told it was the pressure sensor, but the technician who brought my keys back said it was the temperature sensor when I asked him. He also said that it had not done a single regen since new - not surprising since the temperature sensor failed at 360 miles.. So the first regen was the one they had forced using VIDA (the Volvo service system).

Makes sense when you think about it - faulty temperature sensor meant that the car couldn't measure exhaust temperature to know when it was hot enough to begin a regen. Because it then didn't do those regens, the pressure sensor detects the higher differential pressure across the filter and brings on the additional 'soot filter full' message.

But he did say it wasn't far off limp mode..

1,240 miles without a regen - my previous car (an Alfa 159) would have done three in that time.

Granted, it was a brand new car so the DPF would have been perfectly clean, and the 1,200 miles took it to 80% full and higher (manual says it's 80% full when the soot filter message appears..).

I've only just started it's third tank of fuel too - it's doing 600+ miles on a tank full (but never getting to reserve level - I manage to get about 67 litres in when refilling, at most..). So it's averaging a shade over 40 mpg so far, which is exactly what the trip computer indicates tank to tank. It's way short of its official book figures, way way short.

[RoyMacDonald]

Originally Posted by cornclose

I've only just started it's third tank of fuel too - it's doing 600+ miles on a tank full (but never getting to reserve level - I manage to get about 67 litres in when refilling, at most..). So it's averaging a shade over 40 mpg so far, which is exactly what the trip computer indicates tank to tank. It's way short of its official book figures, way way short.

Brand new diesel engine in the winter. No way will you get near the Gov. test mpg yet. Take a reading after 12k and in the summer.

[Chrismmoore]

A faulty cheap MAF caused the same alarm for me

[Daz Newell]

I have been having this problem for over a year now.
When it first happened I had gone on holiday over 200 miles on motorway then 4 or 5 times we used car around there then on way home I give it some throttle and the 'soot filter full' came on...read up on google what to do and after approx. 30 miles it was back to normal but still went into limp mode with code on if given a foot full.
I had it into local garage after one morning it was like it couldn't breath,,wouldn't rev up anyhow they blasted the dpf out and all was well...for about 2 miles ir really went as it used to do but then into limp mode.
I took the large black pipe off that goes from top of engine to egrand it was nearly blocked solid with the dreaded gunge....I have sourced a video on you tube to clean the egr so am going to do this soon.
My car always re gens itself if I travel around 30 miles with revs at 2500-3000.
Really need to sort this but its an 07 and don't want the expensive garage bill.