I have a PC300-5 Komatsu excavator and the RPM's are jumping up and down, the governor motor is shaking and we've looked it over wiring harness and it seems to be okay...also, the power is not shutting off with the key in the OFF position. We've installed a battery switch just to shut it off. Does anyone have any ideas on where to start diagnosing the issue. I also have a PC220-6 with similar problems with governor motor.
Do you know about the mirrors behind the operator seat on the side of the cab towards the boom. There are two fold out small panels that have mirrors and when you look straight down on them on one there will be two red figures. S2 is the usual when things are working right. The other window has three diodes, a red, green and a red. When things work properly only the green will show. Let us know what you see.
There is one green light and one red light and 52 and 25 and 23 are showing up.
We got it. It was a diode. Thanks for the help!
Good work! Do you know the number of the diode that was bad?
I have a PC 220-6 and the govern motor is not working correctly, it is just vibrating. I traced back most of the wiring harness, we unbolted the cap and moved it to the side. The wiring harness looks pretty good, I checked all the diodes in cab and they're all good. I fixed the EO8 plug in the harness, it was not the allowing the speed sensor to work correctly. The pump controller green light stays lit but the govern controller blinks the green light. If I turn the key on, the light stays lit, as soon as I turn up the speed control and then turn it back down, it starts flashing. Right now the only code I have in the monitor is E316. If I turn the machine on and hold the injection pump open a little bit and run the machine it goes in and out limp mode. If I raise to boom up and down, sometimes its fast, or slow. I noticed if its moving slow and I touch the track pedals it goes fast again. Also, I replaced the speed control potentiometer because when I tested it with the multi meter, if I tapped it, it was giving me different readings.
Also, I plugged in a govern motor from a different machine and it was doing the same thing. Also, I ohmed out the wires from the govern motors into the cab. I was thinking that the gov. controller was bad, but I wanted to get your opinion before I spend the money to replace it. The serial number for the machine is A82232 in case you might've needed it. Thank you John
E316 is abnormality in governor motor step out. That would seem to indicate the governor motor has something wrong. Did you disconnect the harness connector to the governor motor and check with an ohm meter for shorts between the wires or if any of the wires are grounded through the motor case?
Okay, I will do that tomorrow morning. I will be getting back to you. Thank you.