Thread: Engine: B5254T2: - DFP Issues - what’s next...
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Old Aug 31st, 2020, 21:27   #1
Volvo XC90 T6 & XC90 D5

Last Online: Jul 5th, 2021 16:13
Join Date: Jul 2020
Location: Marple
Arrow DFP Issues - what’s next...

Hi all,

So after doing a ton of work on the engine, writing it off on a rock, buying it back and repairing the sump, I return to the dreaded “Soot filter full” message.

So what to diagnose next.... here is what has been done:

1) Engine flush
2) Oil change to. Liqui Moli 0/30 low sulphur synthetic oil
3) PCV - valve replacement
4) Breather system clean
5) Oil pan removal, flush and clean
6) Turbo replacement
7) Replaced the resonator box with a resonator pipe
8) Additive for hydraulic valves
9) Additive for valve guides
10) Ceramic coating adaptive
11) No smoke additive
12) DPF pressure sensor replacement
13) DPF pressure pipe work Inspection and clean
14) VIDA Compression test - all in keeping and in tolerance
15) VIDA Injector test - all in keeping and in tolerance
16) VIDA Static regen
17) Clean / decarbonisation of the intake system

After all this I am still getting this dam warning message....

So, when driving the car if I drive carefully and low revs I can prolong the gap between filter full warning. If I put my foot down in first and second gear I can pull up the code immediately.

I have also inspected the charged system many tines as I’m convinced it could be an airleak but I cannot see any leaks. Pipework is all sorted or shows no sign of failure or leakage.

If there is a leak then it must be in the intercooler but there are no signs at all.

Now this is the interesting thing.

After a static region the DPF such value drops to 0. However, it quickly goes up to 20 and then continues up to 26/27 when the Soot filter warning light comes on. Once this activates it slowly counts down and it doesn’t matter whether the car is running or stopped but in 12 minutes the counter would’ve gone back down to about 22. The warning light then goes off and I drive the car again for a short time until the soot filter warning light comes on again.

And here are my thoughts in no particular order:

1) Remove and clean the EGR valve - VIDA shows it is operational but I cannot see huge movement in the valve - how far does it move?
2) Perform a leak off test on the Injectors as they could be taking a dump?
3) replace the intercooler?
4) replace the DPF!

Any thoughts on how I can diagnose this further without spending a ton of cash working out what the problem isn’t?

As always, your help will be greatly appreciated. Hopefully as well with my reporting back this may help others also.


Last edited by NMB; Aug 31st, 2020 at 21:29.
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