From what I read on the following link, the amount of fluid added is in proportion to the amount of fuel added.
http://c4owners.org/plugins/faq/faq.php?0.cat.10.44
If so, chances are that the EOLYS ECU is connected to the BSI via CANBUS & somehow so is the filler cap sensor. Are there actuator tests for the EOLYS pump & the fuel cap sensor? Sorry, am not a Diagbox user so don't know exactly where to look, but in Lexia there are various indicators / test to show for example if the clutch pedal is pressed & to make the AC compressor engage.
http://c4owners.org/plugins/faq/faq.php?0.cat.10.44
If so, chances are that the EOLYS ECU is connected to the BSI via CANBUS & somehow so is the filler cap sensor. Are there actuator tests for the EOLYS pump & the fuel cap sensor? Sorry, am not a Diagbox user so don't know exactly where to look, but in Lexia there are various indicators / test to show for example if the clutch pedal is pressed & to make the AC compressor engage.