The Sauer‑Danfoss MC300 AT322362 is a hardened multi‑loop microcontroller used to drive electro‑hydraulic systems in mobile off‑highway equipment. Common failures on this unit include power‑rail over‑voltage or under‑voltage, shorted I/O lines, and burnt‑out protection diodes on the board; these often manifest as loss of hydraulic response or intermittent error codes. First‑check diagnostics: verify 12/24 V input voltage and regulator output with a multimeter, inspect the PCB for burn marks or solder bridges, and read any stored fault codes via the CAN interface or local diagnostic port. If power and I/O appear sound, proceed to test individual loop outputs against expected pressure curves and check for stuck‑in‑position solenoids.[oss-gpt-20b]