Bought my A4 (B7) 2008 privately yesterday morning, and didn't notice till last night that the ECON is on all the time. After a quick google it seems likely cause/s can be faulty A/C thrust pressure sensor and/or low level gas (either lost over time or due to leak).

Don't want to buy sensor (and remove bumper etc) if not needed, so I intend just regassing first to see if that fixes it.

My question is, can the sensor be removed with system under pressure? Or will I lose all the fresh gas (and cash)?

Intuition tells me it's not a good idea, but there are write ups online that say it can be done.

Thanks in advance

Hi, I had exactly this last week - I'd done 75k, same car as you, and to my knowledge the aircon had never been charged, Phoned round local garages found one who had the gear to do it and £40 cash 40 mins later it's perfect, just as summer comes! I noticed the guy pop the cap off one of the connectors before he began and put his finger on it, looked at me and said "low pressure", i guess he'd know doing them all day. The ECON light is a safety feature - the ECU won't run aircon with no pressure to prevent damage.