Caterpillar TH31-C9T Injection Pump Solenoid Valve is a replacement solenoid assembly for Cat HEUI fuel-injection pumps used on Caterpillar C-series engines, including C-7, C-7s, C7.3, C-9, and C9.3. The solenoid is energized by the engine control system to actuate the injection pump's actuation valve, regulating high-pressure fuel delivery and injection timing. CAT service literature and replacement-part catalogs list TH31-C9T as the solenoid assembly used with these pumps, making it the correct replacement part for compatible engines.
