AC Fault codes

Wanted to know if you need tech stream to see AC fault codes besides the self diagnostic or will any obd scanner show them?

Also for a while I've been getting 21 and 76 and I have the troubleshooting pdf on 76 but

Today I ran the self diagnostic and along with the usual 21 and 76 I got 33 for just miilleseconds before 76

and then later also 42 randomly but now it's back to the regular 21 and 76.

Could the problem exists but the codes aren't quite wanting to set?

Wandering if some deeper electrical/computer problem could be causing delays in codes setting?

This happened with my brake accuator which was faulty making noises driving me crazy for half a year before the the lights finally flashed and codes set to where I was covered by the extended warranty finally

Last yeat took to Toyota and the diagnosed that needed to replace servo air mix door $850 and that would fix my intermittent AC problem but it didn't (5 visits)

Wandering now if they checked the harness from the amplifier and the amplifier itself

Please need help as this may be my home as it has been before. Prius Camper. Not very pleasant without reliable AC