regen
 

How do I know if the particulate filter is being regenerated

You don't , it carries out in the background as you drive around ...

I think that you get a message only when it becomes to full with soot. I have never seen this message on my car. I have noticed that the instantaneous mpg shows much lower when it would normally be much higher at certain times and the mpg being lower than it should be, then after a time the instantaneous mpg readout returns to its normal readings and the mpg goes up, this is I assume when it is regenerating the dpf.

There are several ways to tell if a regen is underway.

- the engine note changes but only really noticeable around town
- instantaneous MPG will drop like a stone
- if you are stationary and external to the vehicle you will notice a loud fan noise from the engine compartment and you definitely smell burning.
- last of all, and most fun if not very 'green', if you plant the accelerator pedal you will see a huge plume of smoke from your exhaust. Particularly vivid on sunny & cold winter day!

^^^^^ That....

Are there times when it cant/wont regen?

I only do a few miles a week, most days its just the dog walk, 2 mile round trip, and 1 day shopping at 11 miles away 3 mile at 70+ the rest ave 55mph. There is the odd rare journey of 60m round trip but mostly A, some B roads

The only time I notice a drop in instantaneous is at the start of a journey when cold, I lose about 10mpg.

Before you say anything, I didn't know about small or slow journeys to be an issue for a diesel, my last car before i traded it in was a 55 plate Laguna 1.9 DCi, had that for about 4 years, same as above driving.

Your 60 mile trip should cover it if it needs to regen.

I have been told that the condition of your heater plugs has a direct effect on regen. In order for the regen to complete satisfactory the heater plugs are used to raise the temp to a high level. Bad heater plugs and the gases fail to reach an adequate temp.

You can use an OBD reader and phone app such as Car Scanner Pro to monitor the DPF. When it regenerates you can see the soot level fall as the temperature of the DPF rises.