air quality sensor/Aircon

[Birty]

During a VW service at SMG Tonbridge my 2011 SE cali indicated a 'static' code /fault prior to undertaking an aircon service. They noted it and didnt carry on with aircon re gas/service. Further diagnostics were required. I said lets wait because the aircon seems to be WORKING! Any thoughts or ideas or is anything a common problem.. They didnt give me any fault codes etc..