Eolys problem

[David I]

C4GP 2016 1.6 Bluehdi 120 - Last year 2025, I had my local garage top up my Eolys (PATS) fluid as a precaution as I had reached 80K miles. I have recently ran a diagnostic Foxwell NT710 on my car and there are 2 Diesel additive codes:

B100C-1C Intermittent ECU supply fault-voltage outside range
B2EB0-00 Intermittent Additive reservoir empty fault

I removed the Eolys tank cover to inspect the tank. When I tap the tank (bottom/sides) it sounds hollow/empty. The wiring all looks good and I tested the pump via diagnostics and there is a clear clicking sound from the pump solenoid. Apart from a tiny smear of black sticky stuff on the top fill connector there are no signs of a leak on the tank, tank cover or in the local area.

I went back to the garage and they said they would have added 1 litre of fluid and that if the tank sound empty then there must be a leak further up from the tank and they would need to book the car in for testing, to which there is a 3 week wait.

If someone could help me with a few questions:

If there had been a leak, would it be obvious (residue of some kind)
Could the tank be full even though it sounds hollow/empty when I tap it
Should I add new fluid myself and check for leaks (process looks simple enough)
Any other areas I should investigate

Thanks in advance

[mickthemaverick]

Have you been into the repair menu on the diagnostic kit and reset the counter to zero?