DPF deep cleaning & hydrogen carbon cleaning

Mostly short journeys: the filter only clears itself when the exhaust runs hot for a sustained spell, so town driving lets soot build up. A fault elsewhere — a sensor, a split pressure pipe, an EGR problem or a boost leak — can also stop it regenerating, which is why we find the cause as well as cleaning the filter.

Yes. The deep clean is done with the filter still fitted, on your drive or at your work. If the readings show the filter is full of ash rather than soot, we'll tell you before any work is agreed, because ash may need the filter taking off and cleaning separately.

The MOT tester records a major fault if they can see smoke of any colour from the exhaust, or find evidence the DPF has been tampered with. A deep clean restores the filter you already have — it stays fitted and working as designed.

Give the car a sustained run on an A-road or motorway at least once a week so the filter can regenerate, and put in a higher grade of diesel now and then. For cars that mostly do short trips, a maintenance clean once a year and a regular hydrogen carbon clean help keep soot down.

A warning light, limp mode or an MOT smoke fail points at the filter, so a DPF clean. Sluggish response, rough idle or falling MPG points at carbon inside the engine, so a hydrogen clean. Many high-mileage diesels need both, and both can be done on the same visit. The diagnostic scan tells us which before anything is agreed.