"ANY CORNER VALVE STUCK OPEN, CLOSED, OR CANNOT LOWER
This is set when the system is unable to make a sensor’s output reach its demanded value."
Are you using EASUnlock to read/ reset your codes?
So could be a sensor problem, or a bag/ line leak (or, of course, an actual valve problem). After the easy bit of checking for a leak, I'd test the sensor with a multimeter to check that it's tracking OK, then swap the sensor with it's opposite number to see if the fault moves with it.