Well, this code is for tiliting valves on 391 trucks.
In the main control valve there are several smaller electrovalves.
Two of them are responsible for the tilt - forwars and backwards.
Check them.
Additionally check the big, 14-pin connector on the control valve.
Eventually, there can be some connection problem with between the previously mentioned electrovalves and the main module N1.
Check the connections on pins 91,92 and 107 on the module.