I bought a 440b a few months ago, but now one of the warning lights on the dash came on. There's no symbol because the lens is broken out. Best I can tell from tracing the wires is this goes to the charge pressure switch? Everything seems to operate like normal though. The only thing that changed before the light came on was that a potential buyer actuated the auxiliary controls with nothing hooked up, I then had to add about 2 quarts of hydro fluid. Is it possible that some air got introduced and now it's not sensing the charge pressure? I haven't run the machine very long since the light came on since I wasnt certain what it was. Any expertise on these would be greatly appreciated.