Galaxy air suspension issues

Sounds like a busted air bellow valve! Common issue on Galaxies with air ride. Have you checked for air leaks around the suspension airbags? Listen for a hissing sound, especially when the compressor is trying to pump it up. That error code is a dead giveaway though. If it won't lift, and it's listing to one side, that valve is likely shot.

Thanks for the quick response! I haven't specifically checked for leaks with soapy water, but I'll give it a shot. Is there a way to confirm it's the valve itself before I start tearing things apart, or is it pretty much the prime suspect given the symptoms?

Given the symptoms, the valve is highly suspect. You could try to diagnose it further with a proper scan tool that can actuate the valves, but honestly, chasing it without the right gear can be a pain. Plus, those valves tend to fail internally. At this point, you're probably looking at replacing the air suspension bellow valve. Get it to a shop to be sure, but brace yourself. I think I would take it to a workshop, because you need special equipment to decompress the system before disassembly.

Thanks a bunch for confirming my suspicions and the advice! I appreciate the input. I'll get it to a workshop. They confirmed it was indeed the faulty air suspension bellows valve, and they've quoted me 590€ for the repair. A bit ouch, but at least I know what the problem is now.