406 hdi 2.2 fuel filter warning (FAP) - Editor
Hi all

Blasted 406 has a new error-says fuel filter needs cleaning (FAP)with a sort of an indicator lamp on the top right hand side of the dash showing a schematic pipe with some dust particles in it. Shortly after the management system light has also lit (the one bottom centre that looks a tad like a brake cylinder) saying Anti Pollution system has failed, which I take as a consequence of this filter not doing it's job. Manual say take it out for a run. Done this-still on. Took battery off for an hour. Still on!

So dearest experts, what do I do? I have googled this, not getting too much that helps back. I mean I don't even know where this filter even is!

Is a 51 plate on 39k miles. Only realy does long runs, apart from over the last 3 days where it has done a few very short ones & was idling for about 20 mins too.

406 hdi 2.2 fuel filter warning (FAP) - Screwloose

Tried Googling "Eolys?" If you've got one of those systems on a 51-plate; it'll be one of the first ones. A passive regeneration needs an average of 50 mph held for six minutes to initiate.

Once the fault light has come on, it may well need a forced regeneration by a dealer to re-set it; ask if you can watch - quite impressive!
406 hdi 2.2 fuel filter warning (FAP) - Editor

Oh I see. I will be going for a bit of burn shortly. Go on then, what's a forced regeneration involve?!

(yes, I can see the Dr Who gag, but I'm not going there..)

406 hdi 2.2 fuel filter warning (FAP) - Screwloose

It may already be too late for an "Italian tune-up." IF [and it's not certain] that you've got an Eolys system fitted; once the light's on it's "Take me to your dealer" time.

A forced regen starts quite innocently. After keying-in "yes" to "Do you, really; really - really - want to do this?" nothing much happens until the rad-fan, HRW, heated mirrors and a few other things switch themselves on. Then it revs itself up to an ear-shattering 4,000 revs...

Ten minutes later, with your hands still over ears, the ECU starts injecting excess fuel into the "Filtre Aux Particulates" in the exhaust and it gets a bit hot - very hot! You don't want to stand within ten feet of the car! On an early occasion this 40-minute procedure allegedly melted the entire front off a 605 parked 15 ft behind. After that they were always done outside; a boiled-away deep puddle and ignited tarmac are only some of the resultant reported mishaps.

The FAP is now on a recommended [50,000m?] change cycle; so there often just replaced. Any excuse to avoid deafening [and poisoning] the dealers' neighbours is usually taken. This cack-handed system is turning-up on all sorts of diesels now - and we're told this is progress...
406 hdi 2.2 fuel filter warning (FAP) - mss1tw
:^D it sounds ludicrous, but I have to confess, I would love to see this being done!
406 hdi 2.2 fuel filter warning (FAP) - LeePower
The forced regeneration cycle is ment to be interesting to watch, The exhaust tail pipe gets VERY hot & has been known to melt things that are nearby in the line of fire, Like other cars bumpers & plastic dustbins.

406 hdi 2.2 fuel filter warning (FAP) - mss1tw
Can anyone put a vid up of this being done?
406 hdi 2.2 fuel filter warning (FAP) - Editor
might just take the camcorder along then, mss1tw! Sounds like you'd be enjoying that utterley irresponsible & oh so childishly enjoyable Brainiac prog on cable-you know the one where they blow things in the name of science!

Screwloose-is it worth me investigating DIY replacment? If so is this filter a dealer part etc?

FWIW it's under Pug's warranty. Also I have a 250 mile mainly motorway trip at the end of the week-sit it at 4k for 20mins at some point?

Always nice to hear from you-thank you for your informative & expert advice. I've another Q about the thing's performance-post it as a new one or as it's a one liner follow on here??

406 hdi 2.2 fuel filter warning (FAP) - Chris S
Does anybody know how a partially blocked fuel filter could have an adverse effect on emissions?
406 hdi 2.2 fuel filter warning (FAP) - Screwloose

Not sure if DIY replacement is a realistic option. It's probably a dealer-only part [anecdotally c.£450 - warranty? No chance!] so it's got to be worth getting a forced re-gen done first. What's odd is that, apparently, it's even necessary on one of the few cars that does appropriate journeys. [Hence my caution about whether it's actually fitted with the Eolys system.]

The earlier filters were cleanable with a pressure-washer; but the rip-off charges for removing the resultant contaminated water are now so ridiculously high that they just get replaced instead. Customers that beefed about paying an environmental charge now happily pay ten times as much for a new one - without a murmur...

As far as I'm aware; once the fault-code is stored, the system stops watching you and waits to be re-set by the dealer - so a long drive may not work: but hey; it's a great excuse if you get stopped for speeding... "I was just initiating a passive regeneration of my particle filter; after all, it's my environmental duty - Officer..."

This thread could run for a bit, as I've a feeling all is not yet apparent; so it's probably better to start a new thread for your supplementary query.
406 hdi 2.2 fuel filter warning (FAP) - mss1tw
might just take the camcorder along then, mss1tw! Sounds like
you'd be enjoying that utterley irresponsible & oh so
childishly enjoyable Brainiac
prog on cable-you know the one where they blow things in
the name of science!

:^D Please do! Yes, I do enjoy seeing that when I can (Unfortunately, we just get peasant, sorry, territorial TV)
406 hdi 2.2 fuel filter warning (FAP) - Editor
hmm, no idea if mine has this eloys system & brief googling not obvious. Perhaps I should call the Pug dealer I bought it from.

Meantime I found this:

snipurl.com/mt3g {Link edited & shortened - DD}

expect there's a cleverer way to have pasted that, but I can't see an 'insert hyperlink ' option.

Back soon


406 hdi 2.2 fuel filter warning (FAP) - Screwloose

Here's some more detail of the very similar Eolys FAP system used on the latest Renaults.

<<< The Official Renault Handover Guide for Diesel Engines with Exhaust Particle Filter.

(These instructions should be followed to ensure diesel engines fitted with an exhaust particle filter (FAP) operate under the best possible conditions.)

What is a FAP used for? To protect the environment: the FAP stops particles being emitted from theexahust system and is currently used only on diesel engines. By filtering the exhaust gas the particle filter stops over 95% of particle emissions.

How does it work? The FAP accumulates the particles of soot and eliminates it periodically by automatic regeneration.

What is regeneration? It is the elimination of soot by high temperatures in the FAP. To make this regeneration process easier, the engine should be used regularly at a sufficient level to ensure high enough temperature of the exhaust gas. During the regeneration phase, high temperatures in the FAP may cause a smell of burning. Especially during the first regeneration.

What does this mean for the customer? There is no particulat issues for the customer except for the specific driving conditions stated below. Regeneration is an automatic process that occurs during normal driving conditions.

Recommendations for driving

Just as fuel consumption may vary, the FAP contamination may vary with driving style. Drive progressively without harsh acceleration to reduce the rate of FAP contamination and to limit the number of regenerations. Driving in this manner also reduces fuel consumption

Warning Note


Specific conditions for Megane II & Scenic II

Vehicle driven for long periods in urban areas:
AT Low Speed
For approximately 180 miles
The message "FAP needs regeneration" or an orange light, or both (depending on the vehicle: refer to the drivers handbook) may appear on the instrument panel.

This message indicates that the FAP is almost fully saturated with soot. If these driving conditions continue, the FAP will be fully saturated after approx 50 miles.

In this case, the advice given is the same as that stated in the drivers handbook:
In order to enable the particle filter to be cleaned, we recommend that you drive the vehicle as soon as possible until the waring light goes out, at an average speed of 50mph (80km/h) providing that the following conditions allow it:
traffic conditions
legal speed limits

Regeneration typically takes about twenty minutes from the moment it starts, if the driving conditions remain favourable. The warning light or the message will then disappear. Nevertheless, if these instructions are not observed, a second warning (service warning light + Injection warning light) may appear. It is recommended in this case that the vehicle be returned to a Renault dealer as soon as possible to carry out a forced regeneration.

Important note: Certain types of operator who drive only in urban conditions, taxi, police, local delivery operators, etc must be made fully aware of the operational requirements for the Megane II & scenic II fitted with this FAP engine prior to purchase.>>>
406 hdi 2.2 fuel filter warning (FAP) - Dynamic Dave
expect there's a cleverer way to have pasted that,

There is - it's called using a url shortener, such as tinyurl, snipurl, or makeashorterlink

Details of which are here:-


ps, I've shortened your link, btw. DD.
406 hdi 2.2 fuel filter warning (FAP) - Editor
I've now just fully read the link I posted myself (thanks DD for the shorthener) & I quote this from it...


The "magic cleaning fluid" is, according to Peugeot, a 'cerium-based Eolys', whatever that may be!

There is a 5 litre container attached to the side of the fuel tank, which contains this substance. Under ECU control, it is injected into the fuel tank by means of an additive injector located on top of the tank.



the thread goes onto to say that the magic cleaning fluid is only released when the ECU works out your travelling at an average of over 60mph. Then says that if you're a taxi driver etc your f*ed. Perhaps not, but it might as well.

Do you believe this? Screwloose-can't be quite right can it? & looking at the forum it came from (BBA), which seems to be a remanufacturers site; coughvestedinterestcough

406 hdi 2.2 fuel filter warning (FAP) - Screwloose

You're not becoming a bit of a cynic are you? My good friend Chuck is rarely - if ever - wrong. Let's just say that he is in a unique position for, privileged, access to almost all vehicle data... [and to set the record straight; BBA-Reman are, without doubt, the most open and honest firm with whom I've ever had dealings.]

The additive is injected in precise quantities into the DERV in the tank. The metal-based [labelled highly-toxic] fluid is then burned through the engine and it's residue remains in the soot trapped in the FAP-filter. This residue [maybe a similar light-metal to magnesium?] considerably lowers the ignition point of the soot; creating conditions that, when desired, permit the deliberate ignition of what is essentially a horizontal chimney fire.

{rest of post deleted at authors request - DD}
406 hdi 2.2 fuel filter warning (FAP) - Editor
well lather me up in magic cleaing fluid & pressure wash me on the patio-triple aplogies all around. Please convey my personal apology to Chuck! On the plus side I now know of another authoratitive forum & had I kept my nasty suspicious thoughts to myself I would be much the poorer.

We'll see what happens after my long trip home on Friday. Thank you Screwloose.

Thought-would me regularly putting in Millers Dieel Plus mess this operation up? Or have contributed to the clogged filter in the 1st place?

406 hdi 2.2 fuel filter warning (FAP) - dieselnut
"well lather me up in magic cleaing fluid & pressure wash me on the patio"
Well I did precisely this to mine about 4 weeks ago.
I have a C5 with the same 2.2hdi & particle filter.
I bought it with 150k on the clock so was due for a particle filter change. Was getting the 'unblock diesel filter' message regularly & if you didn't go for a run the message would change to 'ESP/ASR & Anti-polution Fault' & go into 'limp home' mode.
I removed the particle filter - undo the clip at the tail end of the combined particle/cat - undo the three 17mm nuts halfway along the filter using a hex socket as the nuts get rusty & may round off. Pull off the particle filter. I soaked it in a bucket of hot water with washing-up liquid for an hour then blasted it both directions with a power washer at least 10 times till the water coming out was fairly clean. Let it drain for an hour, bolt it back up with just the 3 nuts then start the engine at tickover. You will get a load of water spurt out which gradually turns to steam. After 5 mins give it a few revs which will dislodge a bit more water then leave it ticking over for a few more mins until the steam subsides. Bolt back up to the rear exhaust. Havn't had any fault messages since & the car is returning about 10% better fuel consumption.
406 hdi 2.2 fuel filter warning (FAP) - Editor
interesting that. Wonder if the one in my 51 plate is the same-see above discussion on has/hasn't it a eolys system.

FWIW I synthesised the advice, took her out just now, waited till all warm, turned on all electricals & booted it for about 1/2 hour in 3rd trying to keep to 70 running 4000rpm. When I 1st started the emu engaged limp home, but about 10 mins after the emu light had gone out I stopped & turned off for about 3 mins, restarted & all was fine!!!

That the end of the story (or at least my part of it) do we all think?

Does the nice pug tell you when this resevoir of magimix is running low, or empty?

Thank you all. If I find a way of telling what one's pug has as it's FAP system I will post it up on here

406 hdi 2.2 fuel filter warning (FAP) - Screwloose

Glad to hear that you've managed to put the light out - permanently[?]

You'll get an "Anti-pollution diesel additive low" warning message if/when the Eolys fluid becomes depleted. It'll then need around five litres at around £32ltr. [What a nice little earner! A dealer reportedly quoted £450+ to refill a 307.]

I've been having a bit of a trawl through all the various 406 HDi wiring diagrams after it occurred to me that any engine code fitted with Eolys would need to include an exhaust pressure sensor.

It would seem [at least from the available data] that engine codes 4HX and 4HW had that extra sensor. Determining whether yours is one of those, is made simpler by the fact that on all later Peugeots, the engine code is incorporated into the letters of the VIN number visible through the base of the windscreen. So if yours includes either of those codes, then you should have the system - probably!
406 hdi 2.2 fuel filter warning (FAP) - Armitage Shanks {p}
If one decided to run one of these blasted Euro 4 compliant diesels with no EOLYS fluid in the system would there be any permanent damage to the engine, exhaust, particle filter etc? Also, is the particle filter replaced or 'serviced' at 72K miles? Replacement is nearly £700, I am told by my dealer!
406 hdi 2.2 fuel filter warning (FAP) - AlastairW
maybe a similar light-metal to magnesium?

Not quite. Cerium is a Lanthanide, whereas Magnesium is an alkali metal. Even more reactive though.
There,knew that Chemistry degree would come in useful one day (15 years later mind you).
406 hdi 2.2 fuel filter warning (FAP) - dieselnut
AlastairW, with your chemistry degree knowledge, would you know if the resultant burnt residue of cerium coated soot would be much of a health hazard. I washed out my filter a few weeks ago as detailed above, the daffodils are still sprouting up through the grey sludge LOL. Or do I need to call in the men in white suits with breathing aparatus to remove.
406 hdi 2.2 fuel filter warning (FAP) - Editor
as my professor of chem mate in the USA was told when he called the US Environmental Agency about a little matter that was concerning him 'if it doesn't glow in the darl we're not interested.' Or words to that effect.

well wretched FAP light came on whilst getting to mway, so did the constant emu light, then the FAP light went off after a blast, leaving the emu one on. Which stayed on with the message 'anti-pollution system defective.', but didn?t seem to invoke limp home performance. Even stayed on after a fuel up. Have just gone back out again, after leaving it for about 2 hours & both lights are now off, but for how long? Grrr.

SL, yes has code HXF in the VIN. Does this mean the patio, sorry someone else's patio pressure wash is now off? Do you reckon this might also have a bearing on the things apparent lack of power-see post re ?pulling??

Thank you all for your thoughts & excellent advice.


406 hdi 2.2 fuel filter warning (FAP) - machika
I had the minimum fluid message on our C5, at around 38K miles (ours is 2.2 HDI auto), immediately after filling the tank. The cost of refilling, at the local main dealar was around £157 and around half of that was for labour. The amount of fluid added was 6 litres.
406 hdi 2.2 fuel filter warning (FAP) - machika
I believe this fluid is supposed to last for 50K miles but I put the shorter interval down to the fact that ours is an automatic, which obviously uses more fuel than a car with a manual gearbox.
406 hdi 2.2 fuel filter warning (FAP) - Editor
sorry all, but the blasted FAP light still keeps coming on intermittently & the car has done no short runs whatsoever. In fact they've all been motorways. It is due a service shortly, but short of a active regen any other thoughts? I'm really tempted to do what one of the other posts suggested & dig it out & clean it manually.

VIN code starts VF38E4HXF..

406 hdi 2.2 fuel filter warning (FAP) - madf
Remind me NEVER to buy a Renault or Peugeot.. Exhaust system that melts things?

I reckon the HSE should do a risk assessment and take them all off the road as a serious hazrd to other people. (seriously.. they appear to be just that and when - not -if- the ECU faults when older and forces this carp system in a traffic jam...
406 hdi 2.2 fuel filter warning (FAP) - Ben79
Remind me NEVER to buy a Renault or Peugeot.. Exhaust system
that melts things?
I reckon the HSE should do a risk assessment and take
them all off the road as a serious hazrd to other
people. (seriously.. they appear to be just that and when -
not -if- the ECU faults when older and forces this carp
system in a traffic jam...

AFAIK the melting only occurs on a forced regeneration, which only the dealers can do as you require a computer and the car revs to 4000+, which you can't really do in a traffic jam!
406 hdi 2.2 fuel filter warning (FAP) - LeePower

The dealer only Diag 2000 machine or on the newer PSA stuff PP2000 machine would be needed to get a forced regeneration going.
406 hdi 2.2 fuel filter warning (FAP) - jimmyw
Do air traffic control know about this, it only needs an apprentice to try it with the car parked on a hill!
does ut store the fault codes? - Editor
Sorry all, sure I posted this bit up elsewhere but I'm screamingly short of time tonight.

Q as in the title? Because the local dealer said that if the warning light isn't actually lit you can scan the EMU till kingdon come & it won't show anything. No real reason to disbelieve but I'm really sure that my bro's volvo 850 stashed everything & had to be flushed at service time.

Thank you one & all.

does ut store the fault codes? - Editor
update time:

Left it all alone & now at 60k miles it has an error message dislaying 'minimum levle of gasoil', which is surely this eol/magic fluid.

Now then: elsewhere & prolly on here there are anecdotal tales of pug etc not being able to source this fluid at one point during their manufacture of their cars, so somewhere there are pugs running about with this FAP removed & pressure detection software etc all disabled.

Question is, how can I achieve this? I've googled & surfed a lot & this info is not out there. Must be able to do it all properly somehow. I'd have thought...

Incidentally, why if I pressure wash the filter, why would I want to run the engine (& all this water business) before tightening it all up?

Thanks hugely.

does ut store the fault codes? - Screwloose

That's not the first time that the disabling question has come up - these infernal things are now much more common [most Euro 4 diesels that don't used Ad-Blue.]

I haven't seen anything that details whether or not it's even possible. [If that tale isn't an urban myth; then they'd likely have just fitted a non-Eolys ECU, or normal software - no; don't even think about it.....]

Never seen "minimum level of gasoil?" [Low on fuel?] It's always " anti-pollution additive...."

If the FAP has been behaving itself; why not get an clued-up independent to top up the tank and re-set the level sensor. The additive is lot cheaper now than it was last year. [Aren't market forces amazing...]
Regarding Peugout 406 2.2HDir - woodman
Would it be OK to fill the offending expensive Eoyls exhaust emissions 6 ltr fluid tank (£35 a ltr for the fluid) under the vehicle with diesel? Then every 10 tankfuls or so put some Eoyls / Cerium based diesel additive directly into the tank (£7 from DMS Automotive Blackpool), mines not complaining! Also the water lancing the filter improves the mpg into the bargain & avoids me paying John Barnett Peugout Blackpool the princlety sum of £530 for "looking at" the problem! LOL "GOOD LUCK" avoiding your Peugout emission system bills! WOrks though, emissions on last MOT were zero .......

Ask Honest John Right column

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