What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks

Why is my car trying to regenerate constantly after the DPF was cleaned?

I have a Ford Focus 1.5 diesel, which I bought very recently second-hand from a main dealer. A couple of weeks ago a fault code indicated a blocked DPF. The garage cleared the DPF under warranty, but recently I have noticed that every time I use the car it is attempting to regenerate, i.e. it has a high idle speed, start stop doesn't work, poor fuel economy. My daily commute is a 44-mile round trip and the car got a 100-mile motorway blast just the other day. I checked the oil and the dipstick shows the level to be too high, I understand that failed regens dump diesel back into the sump and degrade the oil. My driving style cannot be causing this issue. Am I looking at a faulty sensor of some sort?

Asked on 29 August 2018 by David

Answered by Honest John
It's trying to actively regenerate too often and I guess you are probably switching off the engine mid active regen, which is what dumps the post-injected diesel into the sump. The engine might work better using Superdiesel. It's very important to keep engine revs above 1500 until the engine is fully heated up because that creates less soot. More than 2000rpm helps to promote passive regen. Don't think that because it's a diesel you can drop it into higher gears at 1000rpm.
Similar questions
The DPF on my BMW 5 Series is blocked. Can I add something to clean it as I only do short journeys, or should I give the car a good run on the motorway?
The DPF on my 2009 Jaguar XF was professionally cleaned after going from amber to red. The car had done high mileage (104,000), so I was kind of expecting it. 13,000 miles after the clean, it went straight...
I've owned a diesel 2013 Volvo V40 for nearly two years and it has now covered 28,000 miles (short journeys since I have owned it). Recently the message 'soot filter blocked' came up. My local garage has...
Related models
Relaxed but still enjoyable to drive, well-equipped for the money, a huge choice on the used market.