hi everyone. i have a 2001-ish komatsu pc228uslc and it has thrown code 44 and it wont throttle up. anyone know what that code is?
My cheat sheet shows this as a problem in the potentiometer feed back system. This is part of what controls throttle on the engine.
Interesting, does this mean it has a potentiometer on the throttle lever of the injection pump John C?
Generally Komatsu puts the potentiometer in the throttle control motor and connects that with a rod to the throttle lever on the governor. There are two wiring connections to the throttle motor. One has three wires which as I recall goes to the potentiometer and the other harness has four wires which powers the motor. On the Dash 5 line I had a ton of problems with those harnesses because they were right under the muffler and subject to a lot of heat which cooked the insulation. It was even worse if the muffler burned through the bottom and the exhaust gas would blow on the wires. The harness connectors were also hung on a tab and if you didn't route the wires correctly they rubbed on the hangers and shorted out. That was the first issue. The second issue was that the motor had nylon gears inside and they would break up or water would get in and freeze the shaft. You used to be able to replace just the pot in the early nineties but then Komatsu transferred a lot of decision making ability to the US and somewhere in the mid nineties they decided they wouldn't sell individual parts. Anyway if the pot is bad, buy a new throttle motor. Hope the problem is the wires. Look them over carefully. Good Luck!
thanks guys. i traced it back to the electric motor. replaced that and it works now. expensive piece!
Thanks for the update. Willie59: it has nylon gears inside the motor that connect the throttle actuating shaft to the potentiometer. The motor is connected mechanically to a Bosch style pump by way of a rod and throttle ball joints. As I recall there is evan a calibration procedure for setting the length of the rod when you replace the motor.