Ok, I'm really hoping someone has seen a problem like this before. First off... the codes from the PVC: 4, 24, 33, 34, 36. None of these codes are in my manual!? The hydraulics are slow to non existent. It first started a couple of weeks ago. Everything was working fine until I ran the throttle up to "E" mode. Then it was like a switch was flipped and the hydraulic pump went to 0 angle and there was no flow to move anything. If I brought the throttle down a few notches towards the "L" position everything started working again. Tried it up and down a few times and then it started working in "E" mode and above. The problem didn't surface again until a couple of days ago, except this time when I start it cold I can't run the throttle up past "L" without the pump going to no flow. If I leave the throttle a couple of clicks under "L" I have hydraulics but no real useable power obviously. The throttle revs the engine up and down just fine but there is no life in the hydraulics past "L". Some functions are better than others. Swing and track work a little, boom up, arm and thumb do basically nothing. If I track forward the tracks will slowly start moving and then pick up speed. While they are picking up speed I can hear a hissing sound coming from the control valve. Pressure must be building because the tracks are moving faster. Then all of a sudden the tracks will completely stop as if I abruptly let off the pedals, except I haven't. I can keep the pedals pressed forward and within 5-10 seconds I can hear the hissing coming back and the tracks start to move again. It will track a short distance and then completely stop again, and the cycle repeats. If I try to move one of the boom or arm functions while on the move that will also bring everything to a halt. With the machine sitting still and the hissing sound coming back I can start to use the boom and arm functions until it randomly stops. Now the really strange part is that after I have gone through a bunch of these cycles and the oil warms up it starts to act more and more normal until its functioning like there is no problem at all! I can then dig for what seems like an indefinite time and it works fine. Any throttle position and all functions work like normal. So far I had a code for the pressure sensor and it turned out to be a broken ground wire inside the connector at the crimp. This is a new harness from china a couple of years ago. That didn't fix the problem, Next I switched out the DP sensor for a known good one. Also no fix. I have an spare good PVC so I swapped that out and it didn't fix it either. At first there were no codes but after a couple of times running it with the problem I now have the codes that are listed at the top. I have back probed the angle sensor and the voltage seems to move up and down with the pump angle. I also back probed the pressure sensor and it's voltage moves up and down with the pressure changes. It seems like and electrical/sensor problem but at the same time it could be mechanical because of how it starts to run fine after the oil gets warmer. I'm confused, open to any and all wild guesses!
Codes 33, 34, 36 are for a -3 series machine . You likely have an aftermarket ” generic” PVC installed. Double check the PVC and EC ground wires for good solid connections,I think the ground wires all bolt to the floor at the operator seat pedestal. Check the “N“ speed harness for an intermittent open ,it wont create a code but will put the pump to minimum angle. Also check the resistance of the N sensor , spec is 810 +/- 240 ohms .
Yes I do, that makes sense that a code would be there for a sensor that does not exist. Ground is tight, none of the wires move. Ok, tested the resistance of the N sensor: A few days ago it was 1040 ohms, right under the limit. Today it was 1144 ohms, almost 100 ohms over max spec. Next, back probed the N sensor to read the AC voltage output: Idle: 0.34V P: 0.48V Almost no change in voltage with each push of the throttle arrow key. I had a new N sensor in a box just waiting for the day it was needed, lucky me! New N sensor comes in at 970 ohms Idle: 1.346V L: 1.418V E: 1.562V P: 1.712V Seemed to change about 0.02V for every push of the throttle arrow key. The problem seems to be gone now, kinda crazy how the resistance was not that far out of spec but the voltage output was way off. Thanks Diesel Dave!