Controller displays F02 – Overspeed shutdown immediately after start attempt

Safety first: Do not repeatedly attempt to start an engine that is tripping on overspeed. Isolate fuel supply and disable automatic start.

• Check actual engine speed: If possible, use a handheld tachometer during a brief supervised start to confirm whether the engine truly overspeeds or if the fault is false.
• Inspect speed sensor: Locate the magnetic pickup or Hall-effect speed sensor at the flywheel housing on the MTU engine. Check for metal debris on the sensor tip, physical damage, or excessive gap to the ring gear. Clean the tip and adjust the gap to the specification in the MTU service manual.
• Verify wiring: Trace the speed sensor harness back to the MTU controller (e.g., MGC/IntelliVision). Look for chafed insulation, oil contamination, or loose connectors. Reseat plugs and tighten terminals.
• Controller configuration: In the controller setup (service level), verify that the number of teeth and rated speed are correctly programmed for the specific MTU engine model. Incorrect parameters can cause false overspeed detection.
• Governor/actuator check: Inspect the electronic actuator or mechanical governor linkage for binding or misadjustment that could allow uncontrolled fuel delivery. Repair or replace the actuator if it does not respond smoothly.
• Test run: After corrections, clear the F02 alarm and perform a no‑load test run while monitoring speed. If overspeed persists, contact an authorized MTU technician to evaluate the controller and governor system.