C5 particle filter additive ???

[numanoo]

Hi My C5 1.6HDi 2007 Looks like the internal pump inside the additive reservoir is not working.... does anyone know if this can be removed/serviced??? Or do I have to replace complete reservoir?

[GiveMeABreak]

The tank reservoirs are complete units with integral pumps and are not separate.

[numanoo]

Hi Marc,
Ok thanks for that. Much appreciated

[numanoo]

I was trying to find out the wiring for the pump in the reservoir.. I wanted to see if there is a signal being sent to the pump or not? What activates the pump? Is it the fuel tank cap? or Flap covering the cap? I thought I maybe able to hear or feel something down at the resevoir when activated ...but so far nothing. I didnt want to go for a complete resevoir if it was something like a line/pipe blockage ?

[GiveMeABreak]

I'll need your VIN to determine the exact injection system used on this vehicle (please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff), as you may have an engine ECU controlled additive pump version or one with a separate additive ECU.

You won't hear the pump at all unless it is injecting a metered quantity of additive and this is only a miniscule amount when fuel has been added. So you wont hear it whirring or making a noise otherwise.

If you have the older version with a separate additive ECU, then it was quite common for these to fail when they came to have the additive ECU counter reset after topping up the DPF additive fluid. It often necessitated a replacement ECU - which weren't too expensive to be honest. So this could be the issue if not the pump.

[numanoo]

Hi Marc Thanks for your feedback.
Im based in France so the document I have is a "Carte gris" Grey Card...like a registration doc in UK.
Not sure what the VIN number is on it?? Maybe VF7**************[VIN obfuscated, can be read by forum staff] ????
I can send a photo of the doc if any use... but not sure how to attach doc on this forum?

[numanoo]

The reservoir was at a very low level when I got the car and had an intermittant anti pollution error. I refilled the resevoir (two years ago) and got ecu reset. It seemed to clear fault for a while. Recently its back. The local garage hooked up their diagnostics and said it was most likely the reservoir pump. This made some sense to me as the level in the reservoir hadnt really dropped at all in the two years... but not sure how quickly it should drop? Its approx half to 2/3 full at the moment.

[numanoo]

Fault usually occurs on roundabouts or giving it some acceleration on steep inclines.... as if somehow the fluid flow or level is effecting a sensor reading in resevoir????

[GiveMeABreak]

Ok, that's fine, I have the VIN which is all I need.

So confirmed that parts shows you have the separate additive ECU, so what I said in my earlier post stands. - these Magneti Marelli units can fail. When this happens, then no additive will be deposited into the fuel tank. So your vehicle will be relying on natural regeneration, which takes place when the exhaust gas temperature reaches 550°C instead of the 450°C required for assisted regeneration.

So it's not so bad if you do long journeys on the motorway, but shorter stop and start journeys may become an issue where the exhaust temperature is not getting to the higher temperature needed to regenerate the filter.

Unfortunately, these control units are no longer available from Citroen, but this is what they are:

Of course, it may well be the actual pump in the reservoir, but a diagnostic with a Lexia should be able to determine which it is.

[numanoo]

Hi Marc

Thanks for your help, very much appreciated.
I will have a hunt around online and se if this separate ECU is available at local breakers ....
I will also see if the garage confirm the reservoir pump... perhaps with a specific code??
I live in a rural area so most journeys are fairly long but not so much at motorway speeds.
The question that came to mind was........ can I just use the "relatively" frequent use particulate filter cleaning additives that that you put in fuel tank when filling up tank with fuel? Rather than relying on the separate reservoir system??

[GiveMeABreak]

I can't say for sure as those products may only be intended for a clean when there is an issue and on those vehicles that may not have assisted regeneration (incidentally Citroen do not recommend any other additives are used). The additive used by the system in the vehicle is very finely metered out according to fuel added. Other additives manually added may have other consequences to the engine fuel and injection system if over used.

A dealer or somebody with a Lexia kit should be able to see if there is any communications with the additive ECU and be able to test the operation of the additive pump, as well as see if there are any fault codes.

[numanoo]

Thanks Marc, I'll steer clear of other additives.. If I get this resolved I'll update the story Again many thanks for your time much appreciated

[numanoo]

Do you know where this ECU is located on the car???

[GiveMeABreak]

If you have the separate additive ECU (and this was on the cusp of changes where the engine ECU took over this function), it will be where item (6) is. But I would certainly get a diagnostic first to confirm whether it is the additive pump or the Additive ECU (if not the engine ECU-controlled version).

Reference	Designation
(1)	Particle Filter Differential Pressure Sensor
(2)	Fuel Cooler
(3)	Fuel Tank Unit
(4)	Fuel Tank Cap / Presence Sensor
(5)	Fuel Additive Injection Valve
(6)	Fuel Additive ECU
(7)	Fuel Tank
(8)	Engine ECU
(9)	Catalytic Converter + Particle Filter (FAP)
(10)	Additive Tank
(11)	Downstream Exhaust Gas High Temperature Sensor

[numanoo]

Ok Marc, Thanks again I will check with garage as to whether pump or ecu