A/C problem (DTC 29,5 & 29,6)

[Kaido Raiend]

Hi!

My friend is having trouble with A4Q 2.8 '95 airconditioning - if engine is hot,
A/C doesn't work most of time but sometimes works... DTC from OBD says 3 codes
13.7; 15.7  and very interesting one - 29.6 which will change to 29.5 after
switching off A/C.. There is no information available for codes 29.6 and 29.5.
He also said, that freezingagent R134 was checked and supposed to be OK.

My friend is on vacation and therefore can't (doesn't want to ;)) see dealer.
Can anybody tell me what these codes mean and maybe even if there is any danger
if he continues driving?

best regards,

kaido