I got a 279d skid steer RCX00378 with I believe an electrical problem or possibly hydraulic. The 2 speed solenoid failed and over the course of a couple months guy has been running it and it’s fine just no 2 speed. Ended up changing it and it was good, then after a hour of running it he parked it and the next time he went to use it the hyd lockout solenoid was failed so he couldn’t use hyd but could run it around and use the 2 speed. So changed that seemed just like a coincidence that they both failed shortly after another. Anyways they were both working for about another hour and parked it then went to use it again and the 2 speed didn’t work. So figured maybe we got a bad solenoid so ended up getting warranty for it(all cat parts btw) then the same thing changed it out and parked it now the hyd lock failed so then the owner decided maybe it was the block and changed that and got 2 solenoids and it worked for a few hours then the 2 speed failed after parking it multiple times running and letting it sit for a day then using it again. Got about 4-5 starts before it failed. Got me thinking either something is contaminated in the hyd system or a electrical fault and failing the solenoids. Only thing is that if u dont fix the problem the other solenoid will work as long as u want it to. Hyd filter was changed a few months prior to the problem and there are no codes on it. Any help is appreciated.
I doubt if hydraulic system contamination would cause a solenoid to fail electrically but I suppose anything is possible. That points to a wiring fault in my opinion. You say there are no Codes. Have there ever been any Codes pop up when a solenoid fails and how are you accessing the Codes.? Also the replacement solenoids you are pruchasing - OEM or aftermarket.?
It’s all oem cat parts. And when I meant solenoid failing I meant I don’t know if something is plugging the valve part of the solenoid causing it not to move or if the solenoid itself is shorting
Right. Gotcha. Change the hydraulic filter, cut open the old one and check for particles in that case.
If there is nothing in the filter, wondering if the ground circuit for those solenoid is too weak, or if there is a floater jamming the solenoids action. Wonder with the quantity of solenoids changed, if as the wiring warms up the circuit fails. Will be watching to see what filter shows up. Simon C
Back‑probe each solenoid connector and confirm correct supply voltage from the ECM/ECU when the function is commanded (2‑speed button, seat bar down, etc.). If the filter and cartridges are clean, focus on re‑doing grounds (clean, tighten, and duplicate the ground path for those solenoids) and repairing any chafed harness segments common to both functions.
I can only get 7-9 volts right out of the ecm back probed and at the solenoid connector, has 3-4 volts when unplugged. Checked with ground wire in connector and frame ground. Solenoids look clean everytime they are pulled, hyd filter was replaced and old one cut open and was clean. Checked resistance between those wires and every other wire off the ecm and nothing even when wiggled harness, the only thing I haven’t tried was running new wires to the solenoids or running new ground wires to frame. Not sure where to go from here
Have you ever tried confirming that with an oil sample analysis, specifically looking at the ISO Cleanliness Code.?
Which connector exactly are you referring to.? I'm taking it that you have an electrical schematic.?
I made up a 2pin Deutz connector to be able to remove the plug at the Hydraulic Lockout Solenoid ( Item # 90 on the pictorial and Location E5 of Sheet 2 of Schematics ) , Then plug in my Breakout plug to the solenoid with the harness being plugged into the Breakout Plug. Then I can see how much voltage is there and whether or not it is dropping out. Will mention you could of gotten 2 made poorly solenoids, but best to check the power to it and to the ground. Might be an idea to check Pins# 81- 86 for the powers and grounds on the Machine ECM in case something is wrong. If those do not have clean power, then don't expect anything else to run properly. Simon C
Why not start by measuring the resistance of the coils on those two solenoids.? To continue the box-ticking exercise how about checking that the installed solenoids are actually the correct Part Number.? 2-speed - 362-3212 - 4.72 ± 0.24 ohms at 20° C Implement lockout - 421-5425 - 7.7 ± 0.39 ohms at 20° C.
Was it the machine ECM Pin # 73 that you back probed or another. It is the feed for the Hydraulic Lockout Solenoid. Simon C
They were first replaced with those part numbers and then talked to the cat dealer parts rep and he said there’s a change up on the block and everything so the owner bought that and had it installed then shortly after the 2 speed solenoid failed. I will check resistance and get back to you
I was checking the 2 speed solenoid plug. Yes I have access to sis
I have not done that. Owner is not interested in doing that because they r convinced the oil is clean
At the ECM or at the solenoid, or both.? It would be a real giggle if the oil is found not to be clean, and potentially the cause of some/all the problems. It would only cost them about $50 to find out. Go figure. How much is all the diagnostic labout rime costing.?
At the ecm and the connector. I recommended it to them but they didn’t want it done. The diag is definitely more then the test would’ve costed lol
I had back probes in ecm pin #13 and #65 for the 2 speed, and ecm pin #15 and #73 for the hyd lock out
New part number (499-1636) is the same for the hyd lock out and the 2 speed solenoid. Resistance is 8.5 Olm’s. The old one is 8.4
I have to take issue with that. You are correct in that 421-5425 updates to 449-1636 (not 499-1636) and has a slightly higher 8.1 ± 0.4 ohms at 20° C resistance specification However 362-3212 is a current number and has not been superceded. IMHO whoever gave you the information that it also updated to 449-1636 was not correct. You can easily check with NPR.
Here are a couple things we need to keep in mind about this unit. Don't know how many hours, but these track machines have more harness problems because of the vibration caused by any track compared to rubber tire. A 10 gauge wire is rated for 50 amps in cold weather, but only 30 amps under the hood of a truck. I have looked at the schematic a few times and here is a couple things: #1 - We have not proven that the Hydraulic Lockout Solenoid which is powered fron Pin#73 ( Implement Pilot Solenoid - 2A ON/OFF Driver 4 ) of the Machine Control ECM has a clean strong trail to the solenoid. It is only 18Gauge ( Not 10 Gauge ) and goes through Conn# 6( Pin#18 Connector ) before entering the Solenoid at Pin#1. We need to disconnect that computer plug ( Battery Disconnected ) and using a 5 amp bulb hooked to power through a multimeter to measure the amperage, connect the pigtail of that bulb to Pin#73 sending the power all the way to the Hydraulic Lockout Solenoid Plug which we leave disconnected. Hook a terminal to Pin #1 of the Harness plug at solenoid and send it directly to a battery negative post. You will need a good battery to test it and if you run it through a meter on DC Amps you can see if the harness starts to heat up and create more resistance after one hour. You can while it is hooked up tug some harnesses, and wiggle Conn.#6 to see if something pops. If some things burns, you will know what to fix. By checking what ever bulb you use first through your meter, you will know exactly if there is a poor connection somewhere or if the wire is compromised by the fact that the amperage will change. I use a 9003 Auto Bulb for which I bought the 3 wire pigtail and use only the 2 wires that draw 5.0 Amps. If you hook a battery Charger to your test battery and put on trickle charge, your battery posts will likely put out around 14.5 volts which is more real than 12 volts for creating heat. This tests needs to be done or you will be firing the parts cannon for another part, and still not know if harness can handle the load. #2 - Did you Voltage drop test the Computers Pins # 81-86 to make sure there is clean power there. Those ones that are Battery Negative should lose less than 100Millivolts back to battery Negative. The little ground strap coming out of the computer needs to be tested back to battery Negative. How much voltage loss did you measure in the Negative battery cables and Positive Battery Cables. Another 20 second test is to check your Alternator For AC Ripple Voltage. some computers do wonky things when sent AC power. There is more tests to do but you need to start somewhere. If any of this is unclear maybe I can explain differently. Simon C
Ok sounds good. I’ll get that sorted out.
Thanks Simon. I’ll get that sorted out