Hi. I have just experienced two flashing DPF warning lights within three hundred and fifty miles of each other. The first one followed a period of time when the car appeared to be trying to regen but did not appear to be completing. Fuel consumption dropped and when on the overrun the reading wasn't showing the usual 999.9 miles per gallon. When the DPF light came on the first time I went on a 12 mile journey at 2.5 thousand revs to force the regen but to no avail and I ended up with a flashing warning light. I took the car to the garage and to be fair they forced a regen at no cost to me. However they presumed there was nothing else wrong and I went on my way. I did a couple of long trips and in less than a week same problem but also noticed a couple of days before that the fuel consumption was around 24 to the gallon on a long trip. Took it straight back this time and they checked it on the computer and it transpires that the O2 sensor or Lambda sensor has failed. Causing a drop in power, really poor fuel consumption but more importantly it runs rich filling the DPF and also preventing it from doing a regen. They are fixing it under warranty but part needs to come from Germany.