Ask Honest John

Most recently answered dpf questions
I have a 2012 Mondeo 1.6 TDCi. I was in a traffic jam and the stop start was not working - the disable light was on and it would not turn off. I assumed it might be regenerating. Is it a mileage or when...
What sort of speed and for how long do I need to be driving for the DPF on my diesel to be working?
I read a lot about diesel DPFs but how do I know when the fuel system is regenerating? I drive a Toyota RAV4 2.2-litre diesel. Nothing comes alight on the dash board and only once did I smell hot oil?
One of the problems with diesel engines for low mileage users is the clogging of DPFs. Petrol particulate filters now seem to be appearing, so are they likely to have similar problems?
I have the opportunity to purchase a well looked-after Nissan Navara 2.3-litre diesel auto. It has 9000 miles and was first registered in May 2016. The owner is fastidious about the care of every car...
I have a 2015 Volkswagen Transporter T5. The DPF warning light has come on four times since last December. I do a lot of short journeys, but try to do a long journey once a week. Three weeks ago I travelled...
My son purchased a 2014 Mazda CX-5 2.2d with 27,000 miles on from a Mazda dealer. It cut out at a roundabout and would not start and the Engine Management light was on. It was towed back to the dealer,...
My friend has ownes a 10-plate Kia Soul diesel automatic for years, he drives around town all the time and never has any DPF problems, so he thinks that his car does not have one, but I think it does....
I just had my car plugged into a diagnostic computer at a garage and the mechanic said the DPF is blocked. I asked if it could be regenerated, but he said it needs replaced. Does £900 to replace it sound...
With regard to the new MoT changes for diesel cars with DPFs, how can I go about keeping my DPF clean? I have a 2017 Ford Grand C-MAX 2017, which I usually use car for city runs. It doesn't get much use...