John Deere RE507981 Engine Control Unit ECU L6 24V for 6125AFM75 - Used

John Deere Engine Control Unit (ECU/ECM), P/N RE507981, marked "ENG CNTRL L6 / 24V." Application: 24-volt John Deere 6-cylinder electronic engine control; the unit's build label references engine serial RG6125A048123 and engine model 6125AFM75 (PowerTech 12.5 L inline-6 family). John Deere control units are calibrated to a specific engine serial number and typically require dealer programming before use on another engine — application not verified by us. Condition: used take-off, untested. Surface corrosion and dirt on the aluminum housing and fasteners, connector pins appear intact, housing appears complete with no visible cracks. No power-up or functional testing has been performed; sold as an untested electronic unit/core with no operational claim. Buyer must confirm fitment by part number, photos, dimensions, engine model, serial number, and application before purchase. Used marine part sold as-is unless otherwise stated. No returns on electrical, used, special-order, or installed parts.