Hey guys ran into a problem where the boom controls wouldn't work to raise or swing the arm in...I went through the wiring harness on the boom fixed a broken wire and thought that would of fixed up the problem..the code i have now is 74 defective PC-EDC Solenoid..Where is this solenoid located? would this solenoid cause these boom controls to not work?
I am assuming you have a machine with an articulating boom which has sensors at each boom joint and a solenoid somewhere in the machine that shuts the function off. I don't have the specific code book for that machine but my PC228 notes show that code as causing the engine to bog down real hard when operating multiple functions. The boom issue should show a 75 or 76 code. I am also assuming the bucket still works. You have and electronic system in that machine that will prevent the bucket from being jammed into the cab when cycled all the way to the left. Check that all the linkages are intact on all the joints of the boom and stick. If they are you will need to make sure all the wiring is intact. The potentiometers can be checked by unhooking them from the wiring and using an ohm meter. You can unhook the rods and move the cranks to see if the reading goes up and down on the meter. I never had much luck fixing those systems as Komatsu never meant for them to come into this country so didn't supply any type of repair or setup manuals for them. Most of the time I cycled the potentiometer to a place where everything worked and then welded the linkages in place. This does bypass the purpose of the system and should an accident occur that involves injury, it will be considered a will full bypass of a safety system and many government type agencies will seek prosecution. Good Luck!
Thanks John. You are exactly right with the boom and potentiometers. I have fixed a couple and been lucky there wasn't a potentiometer problem usually just a broken wire I found and repaired. These UU's really are a pain to work on but thanks for all the information!