Hello, i'm having an issue with the swing locking up when only swinging. when ONLY swinging a short distance, the house will lock. However, if you pull a different function at the same time as a swing, it will not lock the house. If you toggle that prolix switch, the house will no longer lock at all, but the machine runs slower and it acts like it's in limp mode. Has anyone fixed this problem? PC200-6. Id appreciate any help!
Have you checked for fault codes? Do you know how to get into the diagnostics? It sounds like the pressure switch for the swing has failed in the open all the time mode. As I recall you can test that from the monitor panel or with a multi-meter on the switch itself.
there are no fault codes. When i unplug the swing solenoid tho, the PO3 code comes up, and there's NO swinging at all. When i plug back in, there's no code. it's weird. the whole left stick, which is the swing and crowd just aren't working right. When you crowd in, it feels like you're tugging on a root... it moves slow, slow, slow, then all of a sudden the machine wakes up and it has power and acts correctly. Where is the pressure switch for the swing?
So we went from a swing problem to a left joy stick control problem? You are going to need someone there that knows what they are doing.
I'm wondering if there's a relation between the swing lock activating when it should NOT, and crowd acting odd at the same time- both pointing to a possible issue with the left side handle? Perhaps a EPC or PPC valve issue. In addition, the machine will not auto idle up when only swinging. it will idle up with all other functions I work on a lot of machines, i just don't have experience with the Komatsu.
Idle up is controlled by pressure switches installed on each hydraulic function of the machine. The swing parking brake function is controlled by a timer in the computer. The pressure switches tell the computer when something is being used. The swing brake when in auto mode is locked on when the machine is started and when nothing is being used. It is released when a pressure switch changes state signaling the computer to release the brake. When all the pressure switches return to their normal state, indicating nothing is being used, a timer in the computer starts counting down and about seven seconds later it sets the swing brake. The issue with the stick may be a separate problem completely or something related to the left side joy stick. If you don't have a service manual, you will need to find someone who is knowledgeable about Komatsu Dash 6 hydraulics and electrical control systems. Trying to hunt and peck at solutions is just digging a money pit.
Thanks for the response, that was very helpful. I do have a service manual, they just arrived recently. Where are the pressure switches for each function located? I assume they're on the pilot circuits? i wonder if i can swap switches to do some quick troubleshooting. thanks again.
Those pressure switches are located right behind the cab on a tall manifold that has most of your ppc hoses connected to that manifold. I've had some problems with those pressure sensors years ago. At the time, Komatsu dealer wanted $130 for one unit. I purchased 5 units from Aliexpress (China) for $125 delivered. All were in authentic Komatsu bags with original seals. You can also find a lot of 6 series parts pretty cheap on Ebay these days. Be sure to check your hoses on the PPC system while you are at it. They can be tough to change out on a job site. Another cause of slow function on a complete joystick can be a clogged filter on the incoming pressure line on the joystick. I knew another contractor that had that issue but when I checked mine, it was clean. That filter is located at the bottom of the joystick.
You can follow the pilot hoses back from the swing function valve to see which pressure switch is for that function and then swap it with one of the others. I think you mean the bottom of the joystick valve. Under the joystick there is a universal joint. I've never seen anything stuck in one of those screens but the question if there were anything in there would be where did it come from. Now you have a real problem.
Treemuncher: Where is this filter on the "incoming pressure line on the joystick"? Screens? I'll have to do some investigating on that one.
It should be at the base of the joystick on the incoming pressure line. Another contractor that I knew had this problem so I decided to check mine. It was clean but then I take extra steps to keep my hydraulic oils clean with bypass filtration and regular cleanings with a filtration cart. The filter or screen looks basically like an extra fitting. I don't remember if it was a screen or sintered bronze type filter but it was on the incoming pressure line at the base of the joystick.
ok great, i will surely check that!