I've had the same issue after a power washing but thankfully after a couple days everything was back to normal.
On this machine, we had a tech come in with the software for the machine since we do not have access to it. After about an hr of diag and a phone call to verify they were pretty sure it was the module that controls the hydraulics down under the joystick behind the kick panel. We had a sister truck (one serial number higher) so we swapped the hydraulic module and the machine was back to normal. Swapped the module back and same issue. We ended up running the part number online and finding a good used module on ebay from germany. Took about 3 weeks to get, but threw it in, and machine has been running ever since.