Fabia VRS A/C Fault VAG COM scan codes

Hi there,

Noticed last week my a/c wasn't really as effective as it has been, scanned it tonight with a vag com cable and it has revealed the following fault codes.

17911 P1503 Load signal from Alternator Term. DF Range/performance/Incorrect Signal

18043 P1635 Data Bus Powertrain missing message f.air condition control

Would these be linked and it there any obvious rectifications for it?

I had initially thought that it just needed the system to be recharged but would this lead to these fault codes or is there something else happening?

Any answers would be welcome as i am stumped.

Cheers

Daz