Bobcat T450 Lift Arms & Tilt Lock Up

[TexomaGrapeGuy]

The lift arms and tilt lock up on my 2015 Compact Tracked Loader after 15 - 30 minutes of operation while using a bucket or auger attachment. The only fault code displayed is M3507 (Hydraulic fan open circuit), usually displaying after 2 - 5 minutes of operation. The fan is turning and the engine temperature is normal so I don't believe this is a real fault. The lift arms can be lowered using the bypass valve, but they still won't lift or tilt until a reset occurs, usually which takes an overnight cooldown. Occasionally, I've been able to reset by raising and lowering the seat bar, or by turning the key ON & OFF 3 times, but that doesn't always work (usually doesn't). I've replaced the Control Valve Poppet Valve, the BICS Solenoid, the battery & the battery ground cable. The Bobcat dealer replaced the ACS Controller, but the lockup returned, again after 15 minutes of operation. Typically the red LIFT AND TILT Valve light flashes on the display when the lock up occurs. The drive system function is not affected.

Any ideas of what is going on? I'm surprised no additional fault codes are displayed.

Many thanks for any help!!