Hi..there.. These do tend have alot of issue with the tank itself/module - they are also known for wiring defects to the tank too.. if Citroen have tried to reset it it and notbeen sucessful in doing so..over riding the system wont help certainly when it comes to the DPF system itself..as that relies on the adblue system to be working properly so as not have a knock on effect and cause issue
The system requires a minimum of ~3.75L to reset. I'm sorry, I misinterpreted your post, assuming that 4L filled it. If that had been so it would indicate an issue. The tanks apparently have a capacity of 17L, so, yes, a fill of 16L would indicate that the tank was close to empty, and hopefully the warning should clear quickly.
AdBlue Tank Replacement / UREA warnings / Emissions Fault / Engine Fault / 700 mile countdown - discussion Citroen c4 cactus. Citroen cactus; 4d ago; 1 78 3d ago
Here, the BMW/VW screw top bottle is like $8 for 0.5 gallons. Bulk size DEF is like $10 for 10.5 gallons! Here's a funnel option, which is likely the way I would go: Refill AdBlue on Passat TDI - YouTube. IDParts.com. 17.7K subscribers.
The Citroen C4 has also just been updated, gaining a 98g/km 2.0-litre engine. AdBlue is stored in a 17 litre tank that can be accessed via the boot. Citroen says the size of this reservoir is
RDOBh.