I consider myself quite knowledgeable about the DPF and regen on my Vectra (1.9 150), but I am not sure what is wrong with it now and any thoughts advice will be welcome.
I had issues about a year ago and kept getting p1901-75 error. Replaced DMF/clutch and error appeared to go away. About amonth ago I had front pipe replaced as flexi joint found to be blown. This has now resulted in p1901-75 errors again. I also get an occassional P2279-11 - air leak detected in intake system which I reckon is related and not a coincidence. I have done alot of very big journeys recently, mainly motorway (e.g scot rtn at 1400 miles in 1 week, inc 2 journeys of 500 miles each) and still get p1901-75. Car will do a dynamic regen even with error code and as always this occurs at 100% DPF sat level. Since issues started after flexi replacement car has had 1 forced regen by vx (free!), and done 2 (poss 3 @ 300 miles after forced regen) itself. Car currently booked in for another forced regen at vx tomorrow (again free!)
I use OPCom to monitor DPF sat level and mileage. This appears to be a direct relationship and I am not convinced takes average MPG into consideration. The rate of soot level build up on my recent hols (approx 1000 miles) where average mpg was 45 due to 3 bikes on roof and roof box and full load was same as on my scotland trip earlier in month where mpg was 50. Also just returned from round trip to London (300 miles) where mpg was 60! and soot level accumulation rate still approx 1%/10 miles.
Following is mileage listed agains DPF sat level and points where erorr code was raised or regen occured. Forced regen done by vx at approx 120077. This would have set sat level to 70% so a regen that I did not notice would have occured 300 miles later at 100%.
121217 85 Est Spanner on, on way home from Scotland
121232 100 Est regen on way home from Scotland
121707 65 error
122065 100 regen
122380 48 122272 - 37% P2279-11 air intake leak detected
122441 54 Est - Error light on
122695 77 Est
It would appear from this that DPF is getting blocked sooner each time - 85%, 65% and now 55%. I have considered this could be due to a partial blockage in DPF or car based regen is not completing correctly or diff press sesnsor is wrong.
EGR is 18 months old and still looks very new and was check by vx and found to be OK. I have not check boost (MAP) sensor but will do so tonight. Vaccum pipes at front of engine are all new, though been wondering if vaccum switch (at front of engine and exposed to elements) is to blame (?). I cannot see any leeks in intercooler hoses, but most are hard to get at. As an aside car has a definite whistle when cold, rises and falls with acceleration at low revs - below 2000, only hear once when cold.I do not believe it is an over fueling issue as amount of fuel used against what I have put it seems correct.
If you have got this far - any ideas?