Quad Driver module and suspension

1994 park ave ultra: I am throwing a QDM code i cant remember which side but all I need to find out is what it monitors so I can begin chasing the problem.
Also: My suspension is sagging. The air compressor runs and my lines are in good shape. What is weird is that when i jack the car up and turn it on the struts fill and when i set it down the car stays at regular ride height untill i put er in gear and roll away, then she sags back down. Could that be the leveling sensor?

Any advice would be great; these are two very annoying problems and i cant go through emissions until the engine light goes away.

Thanks

You will need the code to pinpoint what this quad driver controls, some year cars only give 26, the driver usually controls the egr solenoid, tcc solenoid, and other high load devices, one of them is overloading the circuit or has an open. Possible leak in the level ride, get it pumped and use a soapy solution on the shock boots and all the fittings to check for leaks.