Deutz Fahr 115mk3 error code

[BDBed]

Could anyone tell me what the below error code means please? It comes on when I shift from H to M and locks out the power shift. Switching the tractor off and then on again clears it. I have been clutching when going between H and M which doesn't bring up the error code. Thanks for any advice.

 

[BK741]

The control unit detects that control line of solenoid Y4 is short circuiting to earth

Take tin cover off p/shift valve behind r/h step check solenoid and wiring.
Check big round plugs under r/h rear cab

 

[BDBed]

The control unit detects that control line of solenoid Y4 is short circuiting to earth

Take tin cover off p/shift valve behind r/h step check solenoid and wiring.
Check big round plugs under r/h rear cab

Thanks I'll have a look.