2.4D (2005 on) 2012 v60 D5 - DPF reading spike with temperature

[Northern Monke]

Evening all, recently picked up a 12 plate v60 D5. Absolutely love the car but have an issue or two.

Something funky is going on with the DFP. Once up to operating temp the soot reading jumps up 11-18gand once it jumps past the threshold (22g?) it's starts to regen which isn't hugely problematic but it kills economy because it's regenerating 3x the normal amount. It also means once it starts it won't stop untill I'm sub 5g and cycle the ignition, all this which means frustratingly I've averaged 37mpg over 800 miles.

Is this likely to be the DPF pressure sensor or is it something else.

One thing I will add is that the spiking is throttle dependant. When off the throttle it will eventually drop back to the correct reading but as soon as I'm back on it it will start spiking again. It's not load dependant as even in 3rd at 70 it will drop when I've lifted off

Example pictures

Spinking with cruise control on

https://ibb.co/tmpyTYQ

After stopping

https://ibb.co/72Pddfv

[Kev0607]

It all depends on driving style. There's a chance the previous owner(s) didn't do much motorway driving. The more cold starts and short drives the car has or had, the more soot that builds up and the more chance the DPF has of regenerating excessively to get rid of the soot.

It could be the DPF pressure sensor, which I don't think are particularly expensive. An easy way to test that is it should read zero when the ignition is on (no engine running). If it says anything else when the engine is off, then the sensor is bad.

If there's no sensor issue or replacement makes no difference, it could be the DPF itself. What's the mileage on the car?

[Clan]

Originally Posted by Northern Monke

Evening all, recently picked up a 12 plate v60 D5. Absolutely love the car but have an issue or two.

Something funky is going on with the DFP. Once up to operating temp the soot reading jumps up 11-18gand once it jumps past the threshold (22g?) it's starts to regen which isn't hugely problematic but it kills economy because it's regenerating 3x the normal amount. It also means once it starts it won't stop untill I'm sub 5g and cycle the ignition, all this which means frustratingly I've averaged 37mpg over 800 miles.

Is this likely to be the DPF pressure sensor or is it something else.

One thing I will add is that the spiking is throttle dependant. When off the throttle it will eventually drop back to the correct reading but as soon as I'm back on it it will start spiking again. It's not load dependant as even in 3rd at 70 it will drop when I've lifted off

Example pictures

Spinking with cruise control on

https://ibb.co/tmpyTYQ

After stopping

https://ibb.co/72Pddfv

The Particle filter forward temperature sensor can fail on these , this will have a fault code. Also you can monitor it with an OBD reader, see if it gives a realistic reading.

[Simmy]

I would check the egr duty cycle to see if its operating within the specified parameters as it could be adding to you soot problem also check that the oil level is not too high. smell the oil to check for and diesel contamination the last thing you need is a diesel runaway when regening.

[Northern Monke]

Thanks for the replies.

I don't think it's a true reflection of the weigh so it's not linked to driving style. It will show 0g before start and then after starting say for example 5g once Its been running for a while and gets warm it will start jumping to between 16-22g and if I pull over or lift off long enough it would drop back to 5.15g which I would expect to be correct. Only when there is throttle input does it start jumping around incorrectly after a few miles.

The DPF temperature seems to be functioning correctly, read ambient before a start and get to around 200-250° before the spiking in soot weight. If the spike breaks the threshold then it goes to 570-600°

I've not looked at/logged egr so I'll have a play with that and see if I can find anything. Was planning on tackling a strip and clean of it at some point soon anyway.

Shows no codes via obd2 except for occasional interrupted regen if it jumps enough to trigger and I don't leave it for a minute before switching off the engine. From my head scratching could it be blockages in the pipes to the pressure sensor? As these pipes are metal they would be temperature sensitive (I'm clutching at straws here)

The one thing I have done is clean the inlet pressure sensor as it was caked in soot and crap. Didn't do the learning reset thing so may do that. Can't imagine that's caused this

[Northern Monke]

Further confusing information,

Drove on Thursday and soot reading was 8.5g did a little driving this morning and when I checked it was 24.8g from a cold start. Not spiking just straight to nearly 25g went for a drive and the regen did its thing I watched as the soot level dropped as expected until it hit zero and the regen stopped.

I'm wondering if it's underreading the level at cold and the spikes while inconsistent are more accurate as there is no way I put an extra 17g in 6 miles.

I'm now more lost than the start, is there any vacuum type lines to the dpf sensor what could be leaking maybe. Or do I just swap the thing out