If anyone else has a similar issue with their car, here’s my experience and solution.
Focus estate, Jan 2012, 2.0 diesel, 95,000 miles
Driving on the motorway an amber information box came up saying “engine malfunction - service now”. Plugging in a fault code reader, number P244C came up “exhaust temperature too low to regenerate DPF”
I took the car for a hard drive (55 miles on the motorway in 4th, giving 3,000 rpm) to get some heat in the exhaust. I was told the DPF wouldn’t attempt a regen with a fault code present so I cleared it before the drive.
Everything was fine for about 300 miles and then I heard the cooling fan and knew the car was attempting a re-gen. The amber info box came up again, same code.
I did some research and found that the fuel vapouriser is often the cause, so I bought a new one. I jacked up the car, saw where it was located and put the car back down! There’s no way I was going to be able to reach the vapouriser and even if I could I wouldn’t be able to put any effort on the spanner. It was a garage job.
I booked it in at a local garage and used FORScan to find out the DPF was 54% blocked. At idle the DPF pressure was 0.6kpa and at 2,000 rpm it was 2.0kpa.
I was told that driving hard would get the DPF hot and it would passively regen so I continued to drive the car. After about 200 miles I got not only the amber info box but also the engine warning light (amber). There was now another fault code which was P2463 “DPF soot accumulation”. FORScan showed 152% loaded, 2kpa at idle and 6kpa at 2,000rpm. I stopped driving the car.
The garage fitted the new vapouriser (I imagine by taking off the exhaust) which was 2 hours labour, and then did a static regen (0.75 hrs labour). I was concerned the car would refuse to do a static regen with soo much soot, but it was fine.
On picking up the car the DPF pressure at idle was 0.0kpa and at 2,000 rpm it was 1kpa. 28% loaded. Based on this I think it proves the vapouriser was at fault because it must now be injecting fuel to have burnt the soot back from 152% to 28%. Even if the percentage was wrong (or reset) the pressures don’t lie.
A bit about the vapouriser:
It’s a pipe. There’s a small fuel pump which pushes fuel down the pipe and there’s a glow plug to turn the fuel into vapour. This burns in the exhaust and burns the soot into particles small enough to go through the DPF.
A bit about regen:
I was incorrectly told the car can passively regenerate the DPF on the motorway. In fact driving on the motorway just tells the system that now is a good time to actively regenerate. This then tells the vapouriser pump to move some fuel and the glow plug heats up. This is when you hear the cooling fan start up and the engine sounds harsh. This should happen every 200 to 400 miles.
Using software the garage initiated a static regen and I was surprised it worked because at 152% loaded I thought the DPF would need to be sent away for cleaning. The static regen gets the revs high (4,000) and makes the vapouriser work overtime. This burns out the soot. This can only be done in a “safe” environment (static, with people and fire extingushers nearby) because the exhaust gets so hot it can set the car on fire.
If you need part numbers:
Vapouriser = 1856982, about £150
Glow plug on its own = 1892119, about £45
I’ll post again if the issue returns but considering the static regen worked (DPF pressure is now much lower than it was) I will assume the vapouriser was at fault and is now injecting fuel.
Hope that helps.