Particulate Emission Filter - Max no of regens reached!?

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Peter Hemmings - 14 Sep 2006 21:48 GMT

Hi,

Sorry this is a repost of a particular (excuse pun) fault on my 307 1.6
HDI which was in for occasional problems with starting.

The garage did an ECU check and it had two Permanent faults:

Pre/Post heating relay!

and PEF - maximum number of regenerations reached!

The garage did a "forced regeneration" and I have asked if this problem
has been corrected or just reset the number of max regenerations!

They said they would be back but I just wondered how all this PEF
regeneration works and on what basis. One representative said it could
be my driving mostly short distances and not getting the revs high
enough, I have asked him to come back and tell me if I am driving wrongly!!

They also implied that the Pre/post problem was due to the PEF fault,

Anyone know how this works and if I an have the wool pulled!?

Cheers

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Chris Midgley - 18 Sep 2006 20:11 GMT

> They said they would be back but I just wondered how all this PEF
> regeneration works and on what basis. One representative said it could be
> my driving mostly short distances and not getting the revs high enough, I
> have asked him to come back and tell me if I am driving wrongly!!

When excess soot is trapped in the particulate filter the engine management
unit starts the regeneration cycle. This involves raising the exhaust gas
temperature to burn off the accumulated particulates. There are 2 main
components in accomplishing this task. The first is a special chemical that
is held is a tank under the car, it's electrically dosed and added to the
diesel. The second part to this is the engine management unit will start to
post inject diesel into the combustion chamber just as the exhaust valve
opens, further increasing exhaust temperature. There is a cost to these
smoke free HDi engines, slightly higher fuel consumption (and CO2) but their
particulate emissions are very low, probably better then many petrol
engines.

The problem is that this regeneration procedure requires load on the engine,
typically, you must be driving at a constant speed of say 40mph for a few
minutes for it to occur and complete the procedure.

If your daily driving cycle does not include a section of moderate speed
driving, plus you've got glow plug / pre heating problems the smoke produced
may clog the filter quicker then it can burn it off.

> They also implied that the Pre/post problem was due to the PEF fault,

It would make more sense if the PEF fault was caused by the pre heating
failure.

> Anyone know how this works and if I an have the wool pulled!?

Probably not, but what is a typical journey for this car, a 2-4 miles trip
across town, or 20 miles on A-road / Mway?

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Philip Western - 18 Sep 2006 20:53 GMT

My mechanic has said Peugot have contacted them and decreed a filter change
should be done every 50K, because regeneration is just not effective enough.
A recon filter is about £200 so expect a £300 bill. I have done 65000 and my
'clean filter' light is pereodically flashing.
Regards phil.

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