Hello, I am working on a hitachi zaxis 230lc -1 excavator with a complaint of all hydraulic functions suddenly slow. So far I've confirmed pilot pump pressure is OK and pilot pressure acting on main spools is within spec. I've used Dr. ZX hand held tool to confirm both pump delivery pressures reach 36mpa. The first time I went out to it both tracks were very slow and all dig functions. Last time I looked at it I checked over fuses and found a 10amp blown (left side 4th from the bottom). The cover is missing and I can't find the fuse diagram in the book for some crazy reason but after changing this 10amp fuse pump 1 woke up and now the right side track and some of the functions are working OK. This could of been a coincidence or because of replacing the blown mystery fuse. The problem that still exists is pump 2 has 0.6mpa flow control pressure which is the base pressure when no function is activated. This doesn't change at all when running a pump 2 commanded function. Any idea what I can look at next? There are 2 hydraulic hoses off the top of each pump regulator going back to what looks like a pilot control valve. thanks
Found the fuse diagram. It is labelled "solenoid" F4 10 amp
Try unplugging solenoid #6 on the Pump2 regulator. See if you gain any Pump2 performance. Report back your findings. .
Thanks I will try that is that the speed sense solenoid?
Solenoid #6- Pump 2 Flow Rate Control Solenoid Valve
Ok I’m more confused now lol that diagram is for a -1 zaxis? It looks just like my pumps but this machine has pilot regulated pumps and the book I’m reading shows that solenoid as the Y3 attachment flow rate solenoid. Either way I appreciate your suggestion will try that and report back.
Yes the diagram is from a ZX230 manual. If your book talks about solenoid Y3 , it must be a Deere 230CLC manual. Different description, same purpose.
Unplugged the issue is resolved. The solenoid ohm tests within spec 20-30. Would this mean a harness/controller fault?
I swapped solenoids with the torque control solenoid and it made no change. Both solenoids key on engine off read 24.5v
I believe the MC controller is controlling the individual ground side of the solenoid. Disconnect the wire harness from solenoid #6 and the MC controller and check the harness for a short to ground.
Ok will check that. I also swapped the hydraulic cartridges between the torque control and the pump flow no change. Has to be electrical as you suspect. I purchased the proper technical manual and it goes into some detail on conditions that command this solenoid on. Seems there is an optional auxiliary pressure sensor and auxiliary switch that need to be on for the MC to power the solenoid. I thought maybe the pressure sensor had gone bad and the feature was working as it should but couldn’t find a sensor other than one on the swing motor which when unplugged made no difference. The machine is plumbed for an attachment and is used with a tree shear (not currently on) but I don’t see either of these auxiliary features on the machine. Just the standard mode switch in the monitor for dig and attachment and the buttons on the joystick for the tool activation. I don’t quite get what the purpose of this feature is would it damage a work tool if it didn’t limit the flow? Are these symptoms I’m describing of very low flow pump 2 the proper function of this solenoid or has it completely failed. Seems it would be too slow to run any attachment. Book doesn’t describe if it’s a variable signal sent from the controller or just on off. The big hint here I think is the fuse blowing. I wonder if the internal circuitry of the MC has failed. Will check the short to ground first as suggested.
In the DR ZX monitoring list screenshot below, the Pump2 flow rate solenoid (highlited) is listed as being proportional.
Thanks. Trying to find where the auxiliary pressure sensor would be looking like that could be the culprit maybe? On JD parts site for 230lc on the auxiliary page it shows pressure sensor on the back side of the pilot manifold. Going to check there and also the harness for a short. Book mentions "front attachment" pressure sensor and "auxiliary" pressure sensor not sure what the difference is. Front attachment sensor is on the swing motor of all places, there is no mention of where the auxiliary pressure sensor could be located.
The “auxiliary“ pressure sensor (if used) is in port “SM“ of the pilot signal manifold. When you can , post the results of the wiring harness test.
Harness disconnected at the MC and the solenoid there is no short to ground. With the controller out of the machine pin A4 which is pump 2 limit solenoid power is common with pin A2 solenoid control power. Pin A3 which is pump 2 limit solenoid ground is not common with any other pin on the controller including A12/A13 solenoid ground control. So the harness seems ok the controller seems ok. SM port has an ORB to JIC that is capped. I don’t see a pressure sensor for auxiliary anywhere. Still not sure what’s turning this solenoid on. Unless the controller only faults when there is current flowing through it
Any chance there is a connection between A3 and the controller case ?
Just checked that as I’m putting it back in and no continuity to case
I’ve got the controller on order, gonna be 2-3 weeks with Christmas before I get it but I’ll be sure to post results. What still throws me is the machine comes with that solenoid whether it’s plumbed for auxiliary’s or not. So surely there would be provisions for the pressure sensor coming out of the controller. Although the operation principles control section does show the pressure sensor as the required input for this solenoid activation the wiring schematics show no input wires to any aux pressure sensor. I can’t imagine the tech installing the auxiliary’s is adding pins the MC plugs? Fingers crossed the controller puts this one to bed.
I’m confident you’re in good shape
Replacement of the pump controller resolved the issue. Now the throttle does not want to calibrate. Installed new controller, throttle range was correct 950rpm low idle 2000rpm high idle. Figured the book says to do the learning procedure after pump controller replacement so might as well do it… that was a mistake. Now the throttle dial does nothing from min thru the first half then I only get up to about 1700 high idle. Always something
Suggest you try below if you haven’t already. .
Thanks this is the procedure I followed. After doing this the throttle dial does nothing from min- until about half. I’ve lost half of the rpm range. Wondering if the throttle motor has failed from somehow doing the calibration. If low idle is set to 950 I only get 1650 or so out of it. Out of nowhere I had it idling in one instance where it dropped to 450rpm I then adjusted the EC arm to 950rpm and had full range.. but wouldn’t shut off with the key. I turned the key back on and it was low idle 1500rpm high idle 2200rpm. This only happened once. EC motor doesn’t turn until dial hits half I think that’s where I’m losing the full rpm range. Dial voltage checks out. Found a service bulletin for resetting the angle sensor in the EC performed this procedure no change.