The Sauer‑Danfoss MC‑200 Controller Module is an environmentally hardened microcontroller designed as a stand‑alone controller for small to medium mobile machine systems, typically used as a dual‑axis valve driver in conjunction with the JS joystick series. Common failure points for this class of controllers include power supply degradation (especially under high ambient temperatures), solder joint fatigue on the joystick input pins, and firmware corruption due to improper WebGPI updates. First‑check diagnostics should verify that the module receives its rated 24 V DC supply within tolerance, inspect all I/O connectors for loose or corroded contacts, and review any diagnostic LEDs or error codes displayed by the onboard status indicators before proceeding with deeper firmware or board analysis.[oss-gpt-20b]