adblue tank worries

[highwood122]

hi, does anyone know how to identify whether or not the adblue cap is breathing, apart from listening for a vacuum. fiatx290 2021

 

[oldiesontour]

I drilled a small hole in mine.But as soon as the weather improves am going to do a trial test with a simple to fit (4 wires) bypass for the adblue system and input and output NOX sensors and particulate sensor,if all goes well I may leave it fitted or just carry it in the glove box ....in case, either way will be worth the cost for peace of mind