2001 C5 2.2HDI - Additive ECU replace and Lexia

[aspire_helen]

To cut a long story short, I am getting a “Permanent Fault – Diesel Additive Tank Pump Control” resulting in the “anti-pollution system faulty” warning. See Lexia photos. Long story available on request (you may get it soon anyway!).

Assuming the “Pump Control” is the Additive ECU, I have ordered a second hand one (why does everything come from Lithuania these days!?). Normally, data from the old ECU should be transferred to the new. Lexia instructs “if it is not possible to retrieve the values, use the tables by pressing the help button”, and talks about “metering laws”. This appears to require internet/Citroen connectivity which I do not have.

Does anyone know what those tables say? Any other advice?

Note this is for DPX42 pre-RPO9492 for the DW12TED4 engine.

[GiveMeABreak]

You should not need connected access to do this on Lexia, but I don't have your VIN so would need this to check the tables.

[aspire_helen]

Thanks Marc
I will double-check my Lexia3 "Help" option in a few days and let you know.

By the by, do you have access to Citroen work procedures, repair schemes etc? And there must be more guidance to technicians how to interpret Lexia - it is not entirely self-evident!! Would you need a donation for that?

[GiveMeABreak]

No there isn't anything - technicians go on training for its use.

[aspire_helen]

My bad. Re-checked "help" and found the additive vs mileage table for DPX42 and Eolys176.

[GiveMeABreak]

This is basically to tell the new additive ECU or the engine ECU how much Eolys additive fluid that has been injected into the system and subsequently how much of the Cerine element has been dumped in grams into the filter.

This is for purposes of calculating when the DPF is due for changing or deep cleaning. As per the tables, if you don't have the quantity from the old ECU, then you can use the tables to estimate it based on the mileage of the vehicle.

[aspire_helen]

Thanks Marc, in my case its a new filter so I would have entered "0" anyway.
I now have a 2nd hand Additive ECU, but I will not fit it yet (no guarantee its serviceable anyway). Although the Ignition ECU is showing a permanent fault with the Additive ECU, the DPF data in the Ignition ECU itself appears good, and the "engine anti-pollution system faulty" only came up once, 125miles ago, when I was fast idling (1500rpm) the engine for 15mins or so (after radiator change - as per manual procedure, but a waste of time, but thats another story). The new DPF has now done 400miles, without regeneration, and the Ignition ECU has logged "1g" of additive through the DPF since I zeroed that . At 1.9g cerine per 60ltr tank, 1g to 2g for 400miles would sound about right. Am I the only one who thinks it is confusing to have 2 "additive counters": one in litres (for DPX42 in the additive tank) and one in grams (for additive, meaning the cerine component in the additive) that is estimated to have passed through the DPF?
Yesterday, I did a 20mile run on the A1 on cruise at 60mph and returned 68mpg. It used to be my daily commuting run so I know that 68mpg in summer temperature is historically above average for the car. I hope to use Lexia3 on the move and record DPF pressure drop and flow rate. So far, I have only used the Lexia with engine off. My best outcome would be for the Ignition ECU to regenerate the DPF when it is supposed to. As the DPF is new and I rarely drive in town/stop/start traffic, it may take a few more hundred miles. If it does regenerate, I will be one happy bunny.
Just in case, I have started searching for how to delete the additive system, but retain the DPF and regeneration ie NOT a DPF delete, but an Additive ECU delete (and adding DPX42 manually on each tank top-up).

[GiveMeABreak]

Am I the only one who thinks it is confusing to have 2 "additive counters": one in litres (for DPX42 in the additive tank) and one in grams (for additive, meaning the cerine component in the additive) that is estimated to have passed through the DPF?

Not really, as they have 2 separate functions. The additive quantity remaining in the tank is estimated only - there is no physical measurement, hence the resetting of the additive ECU being so important when it has been topped up. It is used by the engine ECU to determine when the tank needs topping up based on the amount injected when fuel is added against the remaining quantity. It uses this information against the maintenance due counter to determine if there will be sufficient miles remaining before the next service for the amount of additive remaining in the tank. If there will be insufficient additive to last, it will flag the top up warning.

As for the other counter for the Cerine, this is for the actual particle filter. Engine deposits ,Cerine and other debris that cannot be burned off are what will clog the filter ultimately - and it uses the cerine weight dumped into the filter to estimate when the particle filter needs replacing. So 2 different purposes.

As the DPF is new and I rarely drive in town/stop/start traffic, it may take a few more hundred miles. If it does regenerate, I will be one happy bunny.
Just in case, I have started searching for how to delete the additive system, but retain the DPF and regeneration ie NOT a DPF delete, but an Additive ECU delete (and adding DPX42 manually on each tank top-up).

Don't forget that the particle filter will 'naturally' regenerate at higher exhaust gas temperatures (circa 550 °C), referred to as passive regeneration. So assisted regeneration will not be triggered unless needed. So you may not perceive a regeneration of the filter in these cases where you are driving under these conditions. Personally, I wouldn't actually change anything regarding deleting the additive pump, or you may introduce other issues and errors. Fingers crossed if you replace the ECU and configure it, all should be well.

[aspire_helen]

The following may clarify the low additive warning.

LOW ADDITIVE LEVEL SENSOR (1283)
A - ROLE
The sensor informs the additive ECU that the low additive level has been reached
when there is 0.3 litres remaining in the additive tank.
Depending on the information received, the additive ECU informs the fuel
injection ECU.
The injection ECU informs the BSI which requests activation of the following:
· request to flash the service LED on the control panel (*),
· request to display a message on the multifunction screen (*).
Note: 0.3 litres of additive is sufficient to fill up the tank 6 times with 80 litres
of fuel (*).
(*) depending on vehicle equipment.
B - DESCRIPTION
The sensor consists of a thermistor.
The information provided varies, depending on whether the thermistor is in the
additive or in air (minimum level reached).
C - LOCATION
The sensor is incorporated into the additive injection pump.

[GiveMeABreak]

That's a bit old now, as in fact there is no longer any level sensor, that function was removed and no longer used.

[aspire_helen]

Yup, Mk1 C5s are all a bit old now! And all my posts are for the 2.2HDi DW12TED4 with Bosch15c2 Injection ECU.

Anyway, I am a happy bunny because I am content the InjectionECU is still continuing to regenerate the DPF despite recording seemingly every fault under the sun for the additive system! So, I have not replaced the additive ECU. The InjectionECU continues to log P1442, P1435, low additive level, additive accuracy fault, additive pump fault. The only 2 additive actuator tests, additive injector and additive pump, do not function. So, as long as I add DPX42 to the fuel tank every time I top up at a dose of 37.5ml per 60ltrs, (so every one of those darling little sooty particles in the DPF will have their coat of Cerine !), the DPF will be fine.

Just for the record, the last regeneration, demanded by the InjectionECU that is , occurred 625miles after fitting the new DPF. The pressure differentials Lexia measured about 50miles later were engine idle (770rpm) =5.9mbar and fast idle (2000rpm) =17.6mbar (compared with 900mb - the maximum back pressure permitted by the engine, and used as a "blocked filter" limit). Moreover, my LED modification (indicating that the regen process had turned on the door mirror demister heaters) showed that the regeneration lasted 8miles of 50-60mph driving. Previously it would take 10 to 11miles on the motorway at 60-65mph. I conclude that this much reduced duration reflects the nearly new DPF. Finally, the "average distance driven for the last 5 regenerations" has risen from 200km to 408km. This is significant because at a value under 350km, the InjectionECU completely ignores the pressure drop across the DPF and reverts to a "distance driven strategy" to determine regeneration ie the more distance the DPF has driven (up to the service limit of 80000km), the more frequent the regenerations are demanded. On that basis, my last regeneration was dictated by distance (due to the 200km figure), but the next regeneration should be determined by pressure differential (due to the 408km figure).And finally, just to be clear, the last regeneration is recorded at the mileage when the regeneration (attempt) ended, not began. More importantly, I believe the figure recorded for "last regeneration" does NOT necessarily mean it was successful! It means a regeneration was merely attempted. The ECU will terminate a failing regeneration attempt when certain limits are reached. So, when I received the "clean filter ASAP" warning 700miles ago, that was as a result of 3 successive failed regeneration attempts, in quick succession, resulting in the low 200km figure for the last 5 regeneration (attempts!). I saw each of the 3 as they happened (due to the LED mod again) but thought they had been successful - clearly not!
All info from the following document available to download online:
CITROEN - TECHNICAL TRAINING
BOSCH HDI EDC 15C2 INJECTION SYSTEM AND PARTICLE FILTER (as fitted with DW12 engines)
DOCUMENT REF N°: 1.6.243 August 2000