Citroen C5 (X7) 1.6 Hdi - diesel additive top up.

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
Bob L'eponge
Posts: 165
Joined: 25 Feb 2013, 13:47
Location:
My Cars:
x 8

Citroen C5 (X7) 1.6 Hdi - diesel additive top up.

Post by Bob L'eponge »

Hi folks,

I know that there is a lot of information around about topping up the diesel additive for the earlier C5 models, but I have found it hard to get some definitive information on the later 'X7' version. Here is what I have found and would appreciate any further info!

I have a November 2009 1.6 Hdi 'Airdream' estate (DV6TED4 FAP) which now has the equivalent of 85,000 miles on it. So far it has been a very reliable and comfortable drive, with the only work I have done on the car being replacing the DMF and clutch at 75,000 miles and fixing a broken cable in the driver's window mechanism using a kit off eBay.

Given the mileage I thought that topping up the diesel additive might be a good idea, even though I had yet to see any low level warning coming up, as most documentation says this will need doing at 80,000 miles for the DV6TED4 FAP engine. So I bought the 3 litre kit of the correct fluid from my local dealer. (Infineum F7995, the latest replacement fluid for Eolys 176, to fit systems using a green clickfit on the tank filler.)

I have previously used version 5.02 of Diagbox with this car, and this has always given some rather nonsensical readings for the fluid level. For example, at 56,000 miles it was reporting that there was '102030 ml' of fluid remaining (i.e. 102 litres!!!) with it not being possible to add fluid to the system. No surprise given that the maximum tank capacity is no more than 5 litres! I took this to be a reading error due to a bug in DiagBox, with the correct amount of fluid actually being 1020 ml, i.e. just over a litre. A recent reading showed just over '61960 ml', i.e 619 ml left. This is where things get strange...

I updated my Diagbox to version 7.15 and updated the interface, and this now gave a sensible reading for the fluid remaining (619 ml) confirming my misreading assumption. So I topped up the tank, which took all 3 litres without any over-flow, and go to reset the additive ECU, which to my surprise does not seem to exist!

I assumed that my car would have an additive ECU and that the engine management system on this car was a Bosch 'EDC16C34_DV6', largely because this is the only set-up referred to for my vehicle in the rather poor Service Box documentation, even when searching by VIN. However, it seems that my particular car might well be fitted with some other variation of the EDC16C ECU, but even Diagbox doesn't say which one, only reporting that it has an 'EDC16C' unit with a PSA references of 96.539.589.80 / 96.648.437.80 (I have been unable find any further information on what these references mean.)

I know that other models do use a system where the additive calculation is done by the engine management ECU itself. For example, the 2.2 (DW12TED4) unit, which uses a Bosch EDC16CP39 unit, but as far as I know this is not used on the DV6TED4 FAP motor. I also know that some C4 1.6 Hdi models are also fitted with a multiplexed additive pump that communicates directly with the engine ECU, and so also have no need of a separate additive ECU. Therefore, there is no reason why I had to have an additive ECU fitted.

Back in Diagbox I could find no reference to an additive ECU anywhere, and selecting 'Yes' to the question 'Does this vehicle have an additive ECU?' returned me back to the option selection screen, suggesting that I recheck the configuration of the vehicle. So, I selected the 'No' option and Diagbox reported that the additive level had been successfully reset. So far so good. Then I did a global test to view the new reading and... it is reporting that there are 1820 ml of additive remaining, even though I put in the full 3 litres. (Which Service Box states is the usual service fill volume for the DV6TED4 FAP model.) Despite this the car runs fine, reports no errors and I am sure the system will be happy with thinking that there are nearly 2 litres of additive in the tank for a long while yet.

Another point that might be of relevance here is the rate of consumption of the fluid. In the time I have had the car (according to Diagbox) it has used less than 100 ml of fluid per 10,000 km driven, with the readings also suggesting that the car was filled with much less than 3.5 litres of additive at the factory. In fact, whilst one section of Service Box says that 3.5 litres are added at the factory for the DV6TED4 1.6 Hdi, another page says that the same model is factory filled with 2.45 litres, and the latest models, such as the DV6C (which is essentially the same motor but with 8 valves instead of 16) with just 1.34 litres. (In fact, my additive consumption figures, along with the mileage, only really make sense if it is assumed that my car was also 'filled' with no more than 1.5 litres at the factory). As far as I can make out, the same tank is used for all models.

So questions.

1) Does anyone know what ECU my car might actually have? If it is an 'EDC16C34_DV6', as the Service Box documentation suggests, can it calculate the functions normally dealt with by an additive ECU, or is another variation likely to be fitted?

2) Why didn't Diagbox report that there were 3 litres remaining after the reset? Is this possibly a bug in Diagbox, or is it more likely that for my vehicle the programmed 'service' replenishment volume is actually just 1.8 litres? After all, as time goes on and the FAP system is further refined it does seem that PSA are designing them to run on less and less additive. Alternatively, does some special procedure perhaps need to be followed as with the earlier models? (No mention of this being the case in Service Box.)

Oh! and why is Citroen Service box so poor, being hard to navigate and seemingly missing a lot of relevant information? :?

Sometimes it seems that running a modern car demands the deductive powers of Sherlock Holmes! :lol:
Last edited by Bob L'eponge on 26 Nov 2013, 08:23, edited 3 times in total.
User avatar
Mandrake
Posts: 8615
Joined: 10 Apr 2005, 17:23
Location: North Lanarkshire, UK
My Cars:
x 664

Re: Citroen C5 (X7) 1.6 Hdi - diesel additive top up.

Post by Mandrake »

Do you have a free service.citroen.com account ? If not sign up for one, as that's the best place to find out the exact specs and fitted components/features of your car based on a VIN number search.

Service box should be able to (used to be able to) do VIN lookups as well but it doesn't work in recent versions - at least in Sedre, so what I do is start by looking up a car by VIN on service.citroen.com then choosing vehicle characteristics.

The information gleaned from the vehicle characteristics page can then be used to select the right vehicle variant options manually in Service box to be sure you're looking at the correct versions of the wiring diagrams etc.
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
Bob L'eponge
Posts: 165
Joined: 25 Feb 2013, 13:47
Location:
My Cars:
x 8

Re: Citroen C5 (X7) 1.6 Hdi - diesel additive top up.

Post by Bob L'eponge »

Hi Mandrake.

Yes, getting a service.citroen.com account would be a good idea. I haven't tried yet as I live in France and assumed that the server would recognise my location and insist on supplying French only documentation. I'll give it a go.

My version of Service Box does do search by VIN and recognises my vehicle. However, the 'Vehicle characteristics' report just gives 'mounting Bosch' for the ECU! Also, even if I do a global model search, there is no variant that seems to match the criteria I am looking for. That is, a C5 'X7' with a DV6TED4 FAP motor but without a separate additive ECU.

By the way, thanks for supplying (in another thread) a link to that page scarymistake distributed for his Diagbox updates. Are you still able to get access to the Auto Professionals site, and if so can you provide any more links to scary's updates? (I am currently on 7.15).

Cheers!
addo
Sara Watson's Stalker
Posts: 7098
Joined: 19 Aug 2008, 12:38
Location: NEW South Wales, Australia. I'll show you "Far, far away" ;-)
My Cars: Peugeot 605
Citroën Berlingo
Alfa 147
x 93

Post by addo »

SEDRE would quantify the connections between additive tank and the engine ECU, including locations of sensors and ECUs (if others apply).
Bob L'eponge
Posts: 165
Joined: 25 Feb 2013, 13:47
Location:
My Cars:
x 8

Re:

Post by Bob L'eponge »

addo wrote:SEDRE would quantify the connections between additive tank and the engine ECU, including locations of sensors and ECUs (if others apply).
Good thinking!

I have just fired up SEDRE and have found that there is no separate additive ECU to be found anywhere in the wiring diagram for the operation of the particle filter. What's more, the fuel additive pump is controlled directly from the engine management control unit, with the filler cap switch reporting via the BSI.

Pity that the Service Box documentation doesn't cover this particular layout!

Still wondering what the full reference is for the engine ECU, other than it being an EDC16C of some sort, and whether that ECU is indeed programmed to reset the additive tank contents to 1.8 litres after a service refill.

By the way, if I set up a service.citroen.com account will I be able to access all the most recent Info' Diag bulletins and so forth? Some older stuff is directly accessible via the link below:

http://service.citroen.com/dtt/IFD/AC/documents/en_GB/

However, later documents must by referenced by something other than their issue number. For example, bulletin 421 deals with configuring the BSI on the 'X7' C5, but taking this URL:

http://service.citroen.com/dtt/IFD/AC/d ... iag409.pdf

and putting in 421 instead of 409 doesn't work.

By the way, thanks for the info / suggestions so far. Better than Citroen seem able to supply in their documentation!
Bob L'eponge
Posts: 165
Joined: 25 Feb 2013, 13:47
Location:
My Cars:
x 8

Re: Citroen C5 (X7) 1.6 Hdi - diesel additive top up.

Post by Bob L'eponge »

P.s.

With regards my suppositions regarding the amount of fluid used in the system on my car, it would make perfect sense for Citroen to try to minimise the amount of additive used as it is the residue from the additive that eventually makes it necessary to change the FAP itself. When I bought the fluid I asked one of the mechanics who was getting something from the parts desk about what was the maximum reside allowed in the FAP before it had to be changed. From what he said I should expect to get at least 200,000 km out of the FAP itself. Now I have done about 140,000 km and, if Diagbox was right, it seems I had enough fluid left for another 60,000, even without topping the tank up, again giving a total of 200,000 km, so perhaps that is the expected service life of the FAP system on these later models. This reduced fluid consumption would also explain why Citroen are putting as little as 1.34 litres in the additive tank of the latest models. After all, why put in 3.5 litres when the car will happily run for 200,000 km on less than half this amount and the unused fluid might 'age' if not used for years on end?

The page below also suggests that the latest FAP systems are supposed to last about 120,000 miles before needing replacement, so that would also tie in with what I have found.

http://c4owners.org/plugins/faq/faq.php?0.cat.10.44

Regardless of the above, given all the reports around that the fluid needs replenishing at around 80,000 miles, including in Citroen's Service Box, I was going to top the system up anyhow, especially given the possibly dire consequences of the system running without fluid. Whatever, things seem to have come a long way since the days when a FAP needed to be changed and 5 plus litres of fluid added after just 40 - 50,000 miles!

This long service life might also explain why I haven't been able to find a FAP listed on any of my usual on-line parts suppliers, such as Oscaro: given the age of the car very few owners will have yet done enough miles to need one.
Bob L'eponge
Posts: 165
Joined: 25 Feb 2013, 13:47
Location:
My Cars:
x 8

Re: Citroen C5 (X7) 1.6 Hdi - diesel additive top up.

Post by Bob L'eponge »

Just a quick update. I thought that the best way to find out what engine ECU is fitted to my car was to simply take a look!

Turns out is has a Bosch EDC16C34_CEM unit fitted. Not sure if this is any different to other EDC16C34 units or not. Whatever, it seems to have the capability to directly control the fluid additive pump without the presence of a separate additive ECU.

So, the only question remaining is what value is programmed into this unit when it resets after being told that the additive has been replenished? I suspect that it is 1800 ml, as DiagBox reports.

I have also found that the service.citroen site does contain information saying that the additive fluid is considered to have a limited shelf life, which would explain why they only partially fill the tanks with these newer system that use much less fluid than those in the past.

Cheers!

Edit. To check the functioning of the system I have just added some fuel and rechecked the additive level. I found that 3 ml of additive had been added for 25 litres of fuel. For most of my driving I average around 5.6 l /100 km (17.9 km per litre). This works out at around 70 ml of additive per 10,000 km of driving. Of course this is not likely to be totally accurate given the small quantity of fuel added, but that figure again suggests that I should use less than 1.5 litres of additive over 200,000 km, so I doubt more than this was put in at the factory.

I have a suspicion that the details given in the Service Box documentation, that give either 3.5 or 2.45 litres as the amount of additive added at the factory, and which say that the additive will need replenishing at 80,000 miles, relate to the first versions of the 'X7' C5 with a DV6TED4 engine, which had an emissions value of 149 g CO2 per km. My version is the later 'Airdream', which was the 'greenest', lowest emissions model available in the range at the time (129 g CO2 /km) so this might explain the differences I appear to have found. Similarly, for the latest 'Euro5' version of the DV6, the DV6C (now fitted with 8 vales instead of 16 and a single over head cam), the specified factory fill of additive is just 1.34 litres.

Bottom line seems to be that the factory aim for a 200,000 km service life for these later FAP systems, and that some of the latest versions achieve on less than 1.5 litres of additive.

Any confirmation, clarification or correction from anyone who has definitive information would still be much appreciated!
Post Reply