Cat 277c skid steer parking break issue, afraid I already know the answer.

[JThomas7]

You said earlier that you got the tech to stop by your machine on his own time. I don't have a problem with that but is he offering to sell you the replacement joystick or did he simply bring one along just to perform a test and now he's identified that the joystick appears to be the problem you have to go out and buy one yourself..? You can see the way my mind is working here .......

I'll repeat that to me it's very unusual for both position sensors on a joystick to go out at exactly the same time - not impossible, but highly improbable. The much more likely root cause would be for a problem in the common power supply or in the common ground. Do you have any way that you could do the Troubleshooting procedures in Post #18 yourself..?

What is your S/N anyway..? Maybe Mark can run something down regarding a Service Letter to double check.

I will have to order a stick from Cat as the one he had is assigned to his truck.
He said he would even come and put it in after I got it and do the calibration procedure.

Yes I will get a multi meter from the shop here shortly and check everything out myself now that I know where to test.


In his eyes from the beginning he said he felt like if it was a bad wire or something like that you would only see it on one sensor, not the other. But I can see what you're saying with the shared circuit.
Did find a service bulletin on 277c left joysticks, but he said my serial # wasn't covered JWF1478

 

[Nige]

In his eyes from the beginning he said he felt like if it was a bad wire or something like that you would only see it on one sensor, not the other.

That comment has me worried, to me it shows that if he has looked at the electrical schematic he never made the connection. If you look at Mark's post #16 above it's clear that the two position sensors in the LH joystick have a common power feed (wire #126 Pink) and a common ground (wire # 203 Black). if you look at the Electrical schematic I posted a while back you'll see that the RH joystick is the same.

Also recall Mark's comment from a few posts back that the most common cause for an FMI03 (over-voltage) Diagnostic Code is an open circuit in either the power or the ground side, i/e/ the two above-mentioned wires.

I guess if I was going to be in for $500+ for a replacement part (did you try Offroad Equipment BTW..?) I would be testing it every which way to make sure that was definitely the fault before I parted with any coin ....... remember to have someone help you and have them pull and twist the wiring harnesses while you drive the multimeter just in case it's a bad contact somewhere. Often they only show up because of vibration which you don't have with the engine off.