1. The aerial work platform cannot be lifted or has weak lifting force
The pressure adjustment of the relief valve does not meet the requirements. Adjust the pressure to the required value
2. Check for leakage inside the cylinder or replace the cylinder assembly
3. Check or replace the valve assembly if the directional control valve is jammed or leaking internally
4. If the oil level is too low or the oil inlet filter is clogged, add sufficient oil and clean the filter
5. If there is a problem with the oil supply pump, check or replace it
6. Check for leakage of the check valve: Inspect the wear and damage between the check valve core and the valve seat, and whether the check valve spring is fatigued or deformed, etc.