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.