Diesel Particulate Filter (DPF)

usher1890

Hi Guys

I have a Honda Accord iDtec 2009 and recently had the warning light for the DPF come on. The warning light usually means two things 1) you can drive for 10/15 minutes for at least 60kph and it will regenerate itself or 2) you need to contact your dealer for regeneration / replacement.

The warning symbol for my car went straight to the second option (i.e. contact your dealer). I had the DPF regenerated on which obviously fixed the problem but two days later the warning light is back on and again straight to contact your dealer.

Does anyone know;

1) Why is it going straight to contact the dealer and not giving me the option of regenerating
2) Should I get it regenerated again or get a replacement?
3) Do you know an approximate cost - I hear it is expensive!

John T Carroll

usher1890 wrote: »

Hi Guys

I have a Honda Accord iDtec 2009 and recently had the warning light for the DPF come on. The warning light usually means two things 1) you can drive for 10/15 minutes for at least 60kph and it will regenerate itself or 2) you need to contact your dealer for regeneration / replacement.

The warning symbol for my car went straight to the second option (i.e. contact your dealer). I had the DPF regenerated on which obviously fixed the problem but two days later the warning light is back on and again straight to contact your dealer.

Does anyone know;

1) Why is it going straight to contact the dealer and not giving me the option of regenerating
2) Should I get it regenerated again or get a replacement?
3) Do you know an approximate cost - I hear it is expensive!

1. Its probable that the DPF sensor is defective, this can be verified by an engine scan.
There are three forms of regeneration, passive which is only effective when the exhaut gas temperatures are hot enough to burn off the soot which is trapped in the DPF. Active regeneration is triggered by the ECU based on the differential pressure sensor (above) which measures the pressure loss across the DPF, when this reaches a certain level the ECU does all sort of clever things like late fuel injection to raise the exhaust gas temperate to a level sufficient to burn off the soot. Forced Regeneration can be enabled by the garage in the event of active regeneration not taking place because of
sensor problems etc.
Eventually, even if everything is working normally, the DPF will get clogged up to such an extent that it has to be replaced as, even continual regenerations, forced or otherwise, will not clear it. In extreme cases, a forced regeneration can cause the DPF to catch fire.
2. The garage should have checked the sensor etc and advised you of any problems, some cars now will tell you if there is a problem with the sensor by flashing the pre heater coil symbol on the instrument panel. (Thats how VW do it anyhow.)
3. Cant give you a ball park number on that, you probably have a separate DPF and Catalytic converter, newer vehicles have a combined DPF and Catalytic converter and I'd say you possibly wouldnt much change out of €1500??. but yours should be considerably less, you can buy "cheap" replacements as well but they might turn out to be more expensive in the long run.

Anosonics

Hi John
The most likely problem with your DPF is that its too badly blocked with carbon build up to self or force re generate . The diagnostics report from the garage should be able to tell you this.It costs 200 euro plus vat to clean in our workshop or we offer a collect and return service for 230 euro plus vat. Hope this helps

Regards
Kevin

John T Carroll

Anosonics wrote: »

Hi John
The most likely problem with your DPF is that its too badly blocked with carbon build up to self or force re generate . The diagnostics report from the garage should be able to tell you this.It costs 200 euro plus vat to clean in our workshop or we offer a collect and return service for 230 euro plus vat. Hope this helps

Regards
Kevin

Thanks Kevin, but surely Usher,s garage should have told him this because if they did a forced regen it means that they have diagnostics to provide a report something like this, attached.

Anosonics

Ya I would imagine garage done a report which should give him a fair idea of the problem. If it shows a blocked DPF I should be able to sort it out.

usher1890

Thanks guys. My father is a mechanic and had a favour done for him the first time - I don't know why it never picked up on it but the second time (also a favour) was done in a garage and it was the sensor so it is fixed now.

John T Carroll

usher1890 wrote: »

Thanks guys. My father is a mechanic and had a favour done for him the first time - I don't know why it never picked up on it but the second time (also a favour) was done in a garage and it was the sensor so it is fixed now.

That's good news. The Golf , above, which is my son-in law's, had the flashing heater coil warning. I have access to a Ros Tech VCDS and it showed up two EOBD faults, P2455 (Short to +) and P2453 (implausible signal), also with the engine switched off it was showing a differential pressure of 70 hpa (mbar?) which was clearly a nonsense. I just unplugged the sensor wiring harness and shoved it back on again and cleared the fault codes. The sensor then showed a diff. pressure of 9.5 hpa when off and 14.5 hpa when idling. I was a bit worried at the 9.5 hpa reading which theoretically should be close to zero so a near neighbour kindly allowed me to read the sensor on his one month old 1.6 TDI Skoda Octavia and it read 6.0 hpa with engine off. So we'll see how it goes.

toyotaavensis

John T Carroll wrote: »

Thanks Kevin, but surely Usher,s garage should have told him this because if they did a forced regen it means that they have diagnostics to provide a report something like this, attached.

Thank you for some of the information necessary to clone your car.
I suggest you edit your post to remove that file before someone actually does clone the car or at least remove the VIN number.

John T Carroll

toyotaavensis wrote: »

Thank you for some of the information necessary to clone your car.
I suggest you edit your post to remove that file before someone actually does clone the car or at least remove the VIN number.

Thanks for your suggestion.
Almost everyone in the country provides (by law) all the info required for cloning, ie the VIN which is displayed in the bottom left hand side of the windscreen, and the registeration number displayed front and rear. The cloner or one of his minions can simply take a few photos with his smart phone of the car with all its details in any part of the country or indeed continent. I did consider not including the VIN in my post but my logic was and is, why clone my car when ALL the info necessary is readilly available in hundreds of Golf's up and down the country?. I certainly would not have included it if it wasnt displayed in public view on the windscreen, I have yet to see anyone obscuring the VIN, it is possibly illegal to do so?.

John T Carroll

John T Carroll wrote: »

Thanks Kevin, but surely Usher,s garage should have told him this because if they did a forced regen it means that they have diagnostics to provide a report something like this, attached.

Had to replace the sensor in the Golf (today) as it was reading 44 hpa with engine off which is way outside any minor deviation, (the DPF warning light was up as well as the flashing glowplug light).What the controller seems to do is: every time the ignition is switched on it transfers the actual diff pressure reading, if any, to a dynamic offset, see items 226 & 227 in attached file, both are presently zero with the new sensor, it then adds or subtracts this dynamic offset to the actual differential pressure and, presumably, if this offset isn't too great then it accepts that the sensor's reading is valid.
This car (son in law's) does a round trip of 130 kms each day, 5 days/week, driven pretty hard and is rarely used at the weekends. It would appear that it still does an active regeneration (whether needed or not) after a fixed distance of around 650 to 700 kms.