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I've got a DPF fault showing in ISTA and lots of soot in the intakes, no matter how many times i clear the fault, it doesn't clear. I've checked the EGR sensor & coolant sensor and both were covered in thick soot, at least 2-3mm thick.. There are also signs of a small oil leak under the turbo. (no splatter, just a blackening metal plate directly underneath). lastly, the air intake (turbo to intercooler and intercooler to EGR) both show signs of oil mist, but not (imo) excessively. (i *think* this is expected?)

The car is a 2011 BMW f11 520d (automatic). N47N engine. To be honest, it still feels quite lively and accelerates pretty well.. :D

I travel approx. 100 miles a day, mostly motorway at around 70MPH. Each journey lasts anywhere from 30 minutes to 1.5 hours.. 99% of the time, it's on cruise control... (yep, i'm lazy!!) The car is (DIY) serviced yearly with bmw approved oil / genuine filters etc.

I've used ista & an icom a2 to read the faults logged and it showed a fault code for the DPF (244800 - info - particulate filter system, limited remaining distance of particulate filter available.

It also showed ISTA code DDE25C800, Exhaust back pressure sensor upstream of DPF - drift outside of tolerance. freq: 5, healing counter: 30, engine idle, rail pressure: 7.84mbar, charging pressure:1003.92 mbar,

I then took readings of the various sensors, both engine off and then running,

warming up
Coolant temp: 47.8C
CYL 1 = -0.4, CYL 3 = 0.6, CYL 4 = -1.2, CYL 2 = 1.0
Exhaust Gas temp before cat:133.2C
After EGR: 55.2C

Coolant temp: 73.9C
before cat:136.7C
before dpf:135.5C
gas pressure before dpf: 962hPa
exhaust pressure before turbine: 1040hPa
charging pressure: 1033 hPa
ambient pressure: 1028 hPa
exhaust back pressure: 1040.0 mbar (absolute)
ambient: 1028.0 mbar

From what i've read so far, I believe the dpf needs removing and soaking in solvent, but not sure if this will clear the error? also, I think the pressure sensor before the DPF needs changing (value above to low) but would welcome a sanity check from those that know :) also, any advice on how to check the turbo, cleaning the intake system or what to check & replace on a car with 120k miles.

thanks in advance
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