Showing DPF Problem, but no codes being read

Hi,
I have a 09 Accord 2.2 DTEC and have the 'Check System' warning light appear on my dash, which usually means the DPF is clogged.

When I brought it to my mechanic, they plugged the diagnostics machine into the car and it reported no DTC fault codes (either temp or permanent codes). We also check the DPF reading which said the dpf was not clogged (very low soot reading). We've used a number of diagostic tools on the car, including Honda's and they all say, no fault codes.

We then reset the PM (Particle Matter) reading, to essentially tell the DPF that it was clear - this worked and the warning light went off. However, once we went 500 metres up the road, the Check System warning came on again. We repeated the reset PM steps, the warning was removed, drove a little and the warning came back.

So it would seem to me that the DPF is indeed clear, but somethign is telling the car that its not.

Has anyone found this type of fault that the car reports, but the diagnostics does not ? It seems like its not really a fault, but I still have the warning light.

thanks in advance,
Aidan

a total guess here, I don't know how the Honda diesel engine does it, but some diesel engines measure a differential pressure across the DPF, maybe that is reading incorrectly

It's not a good idea to clear the ash counter data if the DPF is blocked or hasn't completed a regeneration cycle, you risk serious engine damage and even fire!!

How long have you had this car? Is there any evidence the DPF has actually been removed perhaps and is the car remapped?

It could be a faulty differential pressure sensor or blocked vacuum pipe leading up to it. Can you get the car up to me in West Yorkshire?

"It could be a faulty differential pressure sensor or blocked vacuum pipe leading up to it. Can you get the car up to me in West Yorkshire? !"

I'm based in Ireland, so no chance of getting it to West Yorkshire I'm afraid.

What I'm trying to determine is what my next steps are. The diagnostics software say ' No Faults' yet the dash is saying check engine.

So is it a case of physically examining the DPF ? Or perhaps examine the various sensors that contribute to a DPF warning, in case the sensors are faulty ?

Your next step is to remove the DPF from the car and check if someone has tampered with/removed the DPF cartridge itself. Secondly have the software checked by a tuner who knows what they're doing with these cars to see if it's been tampered with.

If you are prepared to send the ECU over to me, I can do this and return the same day. Drop me a line for details.

Newbie..... did you ever get this issue resolved?