How to Know When the DPF is Regenerating

In this video, discover three signs to know when your car's diesel particulate filter (DPF) is regenerating, so you don't interrupt the process. This procedure only occurs when the engine is warm: the difference is no more than a hundred RPM, with a deeper, duller sound; the noise difference is quite noticeable, as demonstrated in the video.

A second characteristic is the cooling fan running at a very distinctive medium speed. The third detail is realised when you turn off the vehicle, indicating that regeneration has been aborted; this will help for future instances.

It is a whistle indicating that regeneration was in progress, which can be heard clearly from inside the vehicle. If regeneration is aborted too many times in a row, the warning light will come on, and it will not be possible to perform it until the fault is reset, which can be done via the OBD port.

Remember, it is possible to install an LED that lights up when regeneration is active, although performing it in a built-up area is not advisable. It is also possible to force regeneration when you are sure it can be done safely, but this is a very technical system (the empirical method is not explained in the video).