Air Suspension compressor

Hi,
Is there any way to tell if the air compressor is worn out ?
When I turn the ignition on I hear the compressor running for about 5 sec but the car doesn't lift.
The air bags were replaced about 18 months ago
I have had a self leveling warning light come on.
It doesn't always come on though.
Thanks for any help.

The car only lifts about 20mm on start up. Difficult to see unless you relate it to a fixed object.

Put it in low and press the off-road height button, and see if it raises.