C5 2.2 Additive ECU

[cachaciero]

i am sure that I have seen the info I want somewhere but can't find it now I need it

Basically the additive low level light has come on and despite sticking in a couple of litres of Eolys the Lexia won't clear it, also it is saying permanent filler cap error
even though on the parameters pages it clearly shows when the cap is fitted and when it's not.

This leads me to believe that the Additive ECU is screwed, something which I am sure I have read somewhere is quite a common problem on early 2.2's, local Citroen garage when quoting for the job of filling the Eolys also made the point that early ECU's were "problematical" and may need changing.

Anybody got any thoughts / experience on this no a way / procedure for clearing the errors. I also believe that there was an improved (pre CAN bus) ECU anyinfo on this would be welcome as well.

[Hell Razor5543]

I believe (but cannot be sure of this) that the system has to be told you have filled up the additive. I think it counts the number of times the fuel cap has been opened, and uses that count to 'guess' when the additive is low. When you let the system know the additive has been topped up it resets the counter.

EDIT; I should have read your post thoroughly first.

[SaabC5]

Can you get the eolys pump to run on the Lexia? A new ecu won't cure it if the pump is knackered (i fell into this trap)

[cachaciero]

Can you get the eolys pump to run on the Lexia? A new ecu won't cure it if the pump is knackered (i fell into this trap)

Yes i can drive the pump from the Lexia I believe the injection solenoid is switching as well so the ECU is not totally U/S just doesn,t want to reset.
The filler cap error is a bit of a mystery though. I have another question about the filler cap does it have one or two magnets? if two I'v lost one .

In answer to another question as far as I can see the early systems only "counted" the amount injected and displayed it as so many grammes in the filter.
There is no actual quantity measurement the only indication is of low level which I believe is a thermistor type sensor so provided it's covered with fluid it should be good, don't know what it equates to in litres though.

[wheeler]

Ive had to replace several FAP ecu's on mk1 C5's for this exact problem, not being able to reset the values once the warning comes on.

[cachaciero]

Ive had to replace several FAP ecu's on mk1 C5's for this exact problem, not being able to reset the values once the warning comes on.

Hi wheeler

Then I guess you would know if the replacement ECU is an "updated" item, I suppose what I am asking is would an ECU from a 2003/4 2.2 be the same part number and if not would it still be o.k to use it.

Would also be interested to know approx. cost of a new one.

Rgds cachaciero

[RichardW]

There are 3 part numbers depending on the age, and therefore the DPF fluid used:

1525 AS 01 PARTICLE FILTER EL CTRL BOX - UNTIL RPO 09491 FOR DPX42
1525 AZ 01 - SINCE RPO 09492 UNTIL RPO 09869 FOR EOLYS 176 (DPX10)
1525 CZ 01 - SINCE RPO 09870

Prices:

Part Number Description Quantity Price excl. VAT Price incl. VAT
00001525AS ECB 145.76 GBP 174.91 GBP

00001525AZ ECB 145.76 GBP 174.91 GBP

00001525CZ ECB 84.23 GBP 101.08 GBP

Hope yours is a later one

[PICASSOCONVERT]

Hello Cachaciero

I have just replenished my Eolys fluid (added 3 litres) to my 2003 C5 2.2HDi estate. It took about 8 goes with my Lexia to get the ECU to reset, but it got there in the end.

Before the successful ECU reset I did a manual regeneration of the DPF (just to see how it worked as the DPF information showed regeneration was happening about every 750km).

I don't know if the low level warning is generated by a thermistor (as you speculated above). My impression was that the ECU is set with the amount of fluid, knows how much is injected each time, counts each time the fuel cap is removed and then calculates the fluid remaining. I have heard that when it calculates there is only 0.5 litres of fluid left the warning comes on. This is only my impression, so don't bank on it. However, it is broadly what Hell Razor5543 said above.

Hope this helps to avoid a new ECU.

David




In 2006 when I had the particle filter and Eolys fluid changed on my 2001 2.2HDI the Citroen garage warned me the ECU might have to be replaced - and it did. However, the total cost of the job then was only just over £450.

[KP]

FYI if the fuel filler cap sensor is showing a PERM fault it will never active a DPF regen. The sensor needs to work for the system to function and no other faults showing either

IMO just disabled the DPF using the lexia and the EGR as well

[cachaciero]

FYI if the fuel filler cap sensor is showing a PERM fault it will never active a DPF regen. The sensor needs to work for the system to function and no other faults showing either

IMO just disabled the DPF using the lexia and the EGR as well

Not sure about the regen but one thing is for sure it will not inject any eolys so the carbon formed in the filter will essentially be "unburnable" even if it does a regen. In my case "if" the cap is in in the correct position the Fuel cap Parameter on Lexia shows the cap as being fitted take the cap of and it shows it as being "non present", however the ECU reports a permanent failure irrespective. Now the question I need an answer to is: Are there two magnets in the filler cap?

Disabling the system? yes something I have long been mulling over, there is little doubt that the system fitted to early 2.2's using DPX42 was a prototype and like all prototypes full of problems, the later systems are a lot better. In principle I agree with filtering out the carbon particulate, however the price for doing so on early 2.2's does seem excessive.

[KP]

IIRC there should be two magnets so that could be the issue or the sensor could be out of whack just enough to not meet the measurement requirements.

Post up the faults you have in Injection and the DPF section please, screen grabs if possible as it could help others help you thru the issue

[dnsey]

If the low-level warning relies only on subtracting the injected fluid from the total fill, there must be a danger of a discrepancy between the actual volume topped up and what Lexia tells the ECU (perhaps if some of the fluid is spilled, or the tank springs a leak, not to mention unscrupulous technicians 'saving' a bit of fluid). In that case, the DPF would potentially clog without warning.
I'd hope that as a matter of good design there would be some sort of backup check.