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Discussion Starter · #1 ·
Hi, a week or so ago I got the DPF Check system-light without any "DPF regen required" warnings before. Long story short: Honda couldn't do a forced regen and told me that the mechanic thinks that the catalyst is broken since that apparently controls the temperature the DPF gets. The car has been remapped and working without any problems for two years (with a lot less DPF regen required-warnings than before the remap), but they said that the remap could mess with their readings and that could be why the forced regen won't work. I will check out the possibility to get it reset to the original software and let them have another go at forcing a regen.

Has anyone here experienced similar problems? Does it seem likely that the catalyst is the cause of this?
 

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How many miles on the car? If you have high mileage, it could be due to the DPF being full with ash - in that case, it has to be either cleaned professionally or replaced.

A defective catalyst could cause incomplete regenerations and cause an overloading of the DPF with soot. Part of the temperature increase in the exhaust gas is caused by "burning" unburned fuel from late injections in the catalyst, not in the engine. You get about 500-560°C EGT before the catalyst, the final 50-100°C are created in the catalyst. You need about 600°C at the DPF to effectively burn the soot, therefore an clogged or otherwise non-functional catalyst would make regeneration hard or even impossible.

What would be needed for further diagnosis would bei the PM value (dealer can read this with HDS) in grams. Regeneration is triggered at 6.6 grams, as far as i know anything above 16g is critical as it might inhibit even a forced regeneration.

I had problems with my catalyst at about 110.000 km, which was noticeable by regenration times which got longer and longer. At about 120.000 km, my DPF was overloaded with ash and needed to be cleaned, since then i don not habe any problems.

A remap could in theory interfere with DPF soot calculation if done incorrectly (e.g. fooling the ECU by changing injector calibration maps to inject more fuel, which is not registered by the ECU correctly and does not show up in the calculation of the air-fuel-ratio which is needed to estimate soot production...), or if some maps controlling the regeneration are altered/deleted.

You need to know wether the forced regeneration ist not possible because of a) function locked out in HDS or something like that or b) fault message in HDS because soot load is too high (in that case -> ask for PM value!).
 

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The problems with modern diesels. *sigh*

If it was me, I'd remove the DPF (possibly the cat also) and get a good remap to turn off the fault code and make the most of the less restrictions in the exhaust!

On a side note, I wasn't aware that the 2007 2.2 had a DPF fitted. Was this in the EU market rather than the UK market?
 

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The problems with modern diesels. *sigh*

If it was me, I'd remove the DPF (possibly the cat also) and get a good remap to turn off the fault code and make the most of the less restrictions in the exhaust!

On a side note, I wasn't aware that the 2007 2.2 had a DPF fitted. Was this in the EU market rather than the UK market?
It was only added to export models where the country mandated they have one.

You could add it to the UK models as an option but it was expensive and why would you want it?
 

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Discussion Starter · #5 ·
The car is a german import and has done 126 000 km. I can't remove the DPF just yet because of stricter MOT rules that will be enforced from this fall here in Norway.
 

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The car is a german import and has done 126 000 km. I can't remove the DPF just yet because of stricter MOT rules that will be enforced from this fall here in Norway.
Hench my first point.

But normally the DPF cleans it self with a long drive where the RPM and speed are steady.
 

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Discussion Starter · #7 ·
Interesting turn of events: Went down to Honda to pick up the car to take it to the workshop that did the remap so they could reset it to the original software, but the DPF error was gone. I'm going to test the car out for a few days and see what happens. Is it possible that the forced regen has worked even though they got an error message on the Honda computer-thingy?
 

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The forced Regeneration might have worked good enough to clear the error. I had a similar case with my car - mechanic started forced regen after a software update, but due to my already bad catalyst the required temperature was not really reached.

However, after resetting the ECU and clearing the PM Counter, which was reading erroneously high because of the timed out regen, there were no further problems.

The only way to really check wether the regen ist working would be to record one regeneration with the HDS in datalogging mode. The Interface module can be set to trigger the recording automatically when certain Parameters are met, i use the ISV (intake shutter valve) position < 90% as trigger. A too small temperature rise after the catalyst would indicate a Problem with the catalys.

At your mileage, this seems likely to be the case. For now, drive the car normally and see if the error message comes on again. In case of an ash overloaded DPF, there is no way to delete the error, even resetting the PM counter will not work. The car might drive normally for a couple of minutes, but after that period the ECU will have figured out that the DPF is blocked via the differential pressure sensor.
 

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Discussion Starter · #9 ·
Thanks for the info :) I'm going away for the weekend in another car, but my dad will try my car out and see if the error re-appears. Do you know where I can get my hands on a HDS myself? I'd rather not have to go to the dealer every time something like this happens.
 

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Discussion Starter · #10 ·
The error came back, so I'm taking the car back to Honda to get the catalyst replaced.
 

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Discussion Starter · #11 ·
Seems like a new catalyst solved the problem. They were now able to run the forced regen.
 

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Did you get it under warranty or did you have to pay for it?

I had problems with regenerations taking longer than usual, after my catalyst was cleaned regeneration times where shortened from 15 - 20 minutes to 10 minutes.
 

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Discussion Starter · #13 ·
My car was imported so I don't think I've got any warranty in Norway. The warranty I had previously was one I bought from the dealer, but that was a horrible warranty that didn't cover much and it expired over a year ago. The price came to about 12 000,- NOK which is about £1150 so it was a costly endeavour to say the least.
 

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Discussion Starter · #14 ·
The error returned after about 1200 km... Does it seem likely that the DPF needs to be replaced?
 

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Hello, it looks like i have problem with catalyst. Today i tried to run force regeneration but it failed with timeout. During regeneration temperature reached only 490°C and after some time it failed. It is possible to somehow clean catalyst or i have to replace it? On HDS i could see that DPF differential pressure is only 0-1 kPa. Is it normal or i have problem also with dpf dif. pressure sensor?
 

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Hey, everybody! I am new to this forum, I am from Bulgaria, so sorry for raising the old topic but I have a problem and I need an advice urgently. I have a 2007 Civic 2.2 i-TDCi. Couple of days ago the DPF CHECK SYSTEM symbol (with the exclamation mark) came up on my display. I went to a diagnostics guy who said the filter is not that clogged, so he did not do a forced regeneration. He suggested that I should go on a 40 km drive and keep her above 2000 rpm and the car would enter DPF regeneration on her own. I however feel that the car will not do it and am afraid that I could do do damage if I do high RPM driving under these conditions. What should I do - should I go back to the diagnostics guy and demand a forced regeneration. Please help! Thank you in advance! :)
 

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forced regen should be last resort
if you can get it to regen normaly then that's the way to go
our 2.2 ctdi's did not have dpf so not many will have experience of the issue on that engine
 

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forced regen should be last resort
if you can get it to regen normaly then that's the way to go
our 2.2 ctdi's did not have dpf so not many will have experience of the issue on that engine
Thank you! I will try driving it then, I am just afraid that it may start diluting oil with excess diesel from driving under these conditions.
 

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OK, some update on the subject. Since the Bulgarian forum members were positive that under these conditions (active DPF indicator with exclamation mark) the car will not start regeneration by itself, I decided not to drive it on a long disstance and went to another diagnostics guy. On the way there I realized that the car is actually in something like e limp-home mode, since it had no power and would not go over 3000 R.P.M. This guy would also not start forced regeneration but he cleared the filter's soot value and the car went out of the limp-home mode. I pushed it qute fast and it was going fine although arguably not at a 100% (not really sure). So now I should drive it out of town with higher rpm and speed and hopefully it will start it's own regeneration. And about the forced DPF regeneration, the second diagnostics guy also said that it is not advisable to do it, because it is not very good for the overal health of the car. It is done not in movement, but at parked position with engine revving and high temperature of exhaust so best to make the car do it on her own and while travelling. If this doesn't work I am thinking of removing DPF and EGR.
312855
 
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