This is like a recurring nightmare I had when I picked up my new 2021 RT LTD.
It threw C210A codes from new...
1. The rod that connects the swing arm to the ride height sensor was never connected at the PDI. I suggest you look to see if yours is connected. This is often the prime cause. Sometimes the bolt was not tight and falls out.
2. The result of this lack of height measurement was that the compressor ran constantly and burnt out.
3. In diagnosing this far they found the pressure release valve was not closing and the solenoid for this was not working either.
4. Then they found a leak in the airbag.
5. The Schrader valve under the seat was found to be leaking too.
This all took about half a dozen returns to the dealer, where the poor tech, who was a good guy, just about tore all his hair out going from one thing to the next.
6. In the end, he gave up and got BRP to send a whole new rear air suspension system and fitted it. It finally fixed it.
All this took about 5 months, though Covid supply chain issues weighed heavily on that.
My Spyder would be fine on surface streets and the canyons, but after five minutes on the freeway it would throw a code. It seems that when I went over a freeway joint that caused the bike to unload the suspension that would cause the problem to indicate.
Now the air system merely sets the ride height. The suspension is actually a regular spring and shock, so it will run fine without the air suspension as long as you don't have too much load.
One way of testing it is to ride around a bit, then stop, but don't turn the bike off and don't go out of gear. Then measure the air pressure at the valve under the passenger seat. It should be about 30 psi.
Try it with a passenger, without turning off the bike or shifting to neutral, an observer should be able to hear the suspension let air out as your passenger gets off and the rider it still sat on it.
It seems to my experience, the air suspension only does things when the bike is on, engine running and in gear. I couldn't rely on the pressure readings when you shut the thing down or put it into neutral.
However, if the bike is turned off, it should still hold pressure to some extent overnight. Don't fill from a compressor, use a hand pump, the volume is small and easily broken from a high volume of air being inserted. Put 30 psi in and see if you have at least some pressure in the morning.
The other thing I found is that the compressor has a non return valve that stops the air leaking back through the compressor. If pressure is completely lost overnight, it might be that non return valve not doing its job.
It is a simple system that has a complicated implementation, all parts of which must be working correctly otherwise many different problems can cause the same fault.
It is a hard problem sometimes for even a good tech to solve.
Good luck, it's worth it in the end but mine was a nightmare to fix.
