JD 160lc travel speed trouble

[mark18mwm]

I hope maybe some one here can help. We have a John Deere 160lc we are having trouble with the travel speed. What it's doing is when it is in high (rabit) it goes into slow speed occasionally with the switch still in high. The problem is getting worse, it used to do it occasionally and return back to normal. Now it does it more often and for longer periods of time but still intermittently. Being a intermittent issue every time we take time to look at it it refuses to do it but put it back to work and it will do it again at some point. We don't know if it might be the switch or i assume there is solenoids someplace that might be not working or even a wire harness issue. Is there a way to "hot wire" from the switch to the solenoids, where ever they are, to see if it might be a harness issue. I guess after that we can start throwing parts (money) at it one piece at a time till we fix it but we would rather not go that route. Anyone have any experience or advise with this? Thanks.

 

[garyw]

What year is the machine?
It could be a number of things. It could be the switch that's faulty. Could also be the solenoid. But with it being so intermittent my moneys on an issue with a sensor or sensor wiring. These are the conditions of the sensors for the high speed travel to work.
Operating Conditions:
Travel Pressure Sensor: ON
Front Attachment Pressure Sensor: OFF
Pump 1 and 2 Delivery Pressure Sensors: Either
pump delivery pressures are low.
Pump 1 and 2 Control Pressure Sensors: Either pump
control pressures are high
If your travelling and either pump control pressures drop lower than spec, If either pump delivery pressure goes higher than spec, If your travel pressure sensor losses it's signal or of the front attachment sensor sends a signal it'll drop to slow speed. There's no easy way to pinpoint the fault without using diagnostic software. You may be able to bring it up on the monitor depending on the year of the machine

 

[mark18mwm]

Thanks for the reply. I'm not sure of the year of the machine, I can find out when I get back to work (off a couple days).I had no idea those sensors did all that. I most likely would not have checked them without you telling me about them. I will have to check them and I guess if I don't find anything I might have to get John Deere to plug it in to see if they can figure it out. I was hoping to avoid a service call but it might be cheaper than down time chasing my tail around on this thing. Boy, I sure miss the days of straight simple hydraulics. Years ago I thought pilot controls were a pain, now I wish that's all they had. I guess I'm getting to damned old to keep up to technology, haha. Thanks garyw, I appreciate it.

 

[mark18mwm]

Thanks to your help I think I'm narrowing it down to the pressure sensors (I think). I was talking to a operator about it and he said a couple times it slowed down while digging also. I didn't know that until now. It also seems one track looses power some times also. So here is my thinking. It appears in the book the tracks operate on one on each pump, that with the new info he told me along with your information one of the pumps pressure sensors might not be reading correctly causing hyd pressure to be diverted to another function or maybe controlling and dropping the output pressure at the pump itself. Does that make sense or do you think I'm chasing my own tail with that theory. Do you know how to test the pressure sensors, and do you know if they have power to them or do they work off a ground? I'm still not back at work, just thinking about it here at home. When I get back I'll find out what year it is and if I can pull up any codes on the machine display. Thanks again for any help, as you might guess I'm not a professional mechanic, just a truck driver who always gets stuck trying to fix this stuff. Edit: I found out it is a 2006 model.

 

[garyw]

I wouldn't read to much into what your operator is telling you at the moment to be honest. Sometimes its easy to get taken off track with too much information. I'd concentrate solely on the travel issue before thinking about the digging functions. I don't think these are related. It sounds strange but the pressure sensors aren't really used for pump control. Their mainly used for valve control. As in, the 2 speed travel valve, various flow control valves in the control valve. I'll give you a brief run down of the pressure sensors. Basically there's all the ones i mentioned on the previous post plus there'll be boom raise, arm in, swing and maybe boom bottom cylinder( optional) They are a 3 pin sensor, the 2 outside wires are 5v and gnd. The centre pin is a signal wire. With the ign on, the controller has to see around 0.9 volts from the signal wire or it throws up a fault. Also if is see's over around 4.6 volts it throws a fault also. This goes for all the sensors. When the pressures increasing the voltage rises and vice versa. The most common issue with the sensor wiring is bare wires around the hyd pump. I'd also have a look at them, mnake sure there's none that are bare and touching the pump body. You may need to monitor these signals to see what they're reading when the fault arises. The issue you have is that it comes and goes. If it was there all the time it would be much easier to find. Also with diagnostic equipment you can clear the fault codes, work it an hour or so till it faults then re check the faults.

 

[mark18mwm]

Thanks, good information. I messed with it a little today. I used a jumper wire to try to pull up a diagnostic code. If I did it right it came up with code11 and in the book they say that it is " Pump 2 {5-spool) Pressure Sensor". So I put pump 1 wire on pump 2 sensor and pump 2 wires on pump one sensor to see if that changed the diagnostic code to a pump 1 fault to test the sensors. It still read as a pump 2 sensor fault even when on pump 1 sensor, which makes me, like you, think it is a wire harness issue also. But when I got home I thought about it, I never cleared the code so maybe it was showing me the stored code again? If that is the case I need to clear the code and try swapping connections again I think. I checked continuity from the plug ins at the sensor to the plug by the computer and they read good but with being intermittent it might read good and still have issues at other times. The machine goes back out tomorrow so I wont see it for a few days to look at it again. In the mean time I brought the books home hoping to get a better understating of the entire system. So far your advise has been my best help, I truly appreciate it. Do you think if we got the dealer out here they could plug it in and find the issue with out spending all day there and not find anything? The closest dealer is about 2 hours away in every direction and we are hoping to tackle it our self but if the dealer can do it quickly it might actually be cheaper to have them look at it.

 

[garyw]

I'm pretty sure that the fault codes should clear themselves whenever the fault has been rectified. It would be easy to test. Pull a plug off another sensor and see if it comes up with 2 codes. Then plug it back in and see if it clears. If its coming up with a code for Pump 2 pressure sensor, and it didn't change when you swapped the plugs then it would suggest an issue with the harness. And with you saying the fault is intermittent then as you say, the harness may have been good when you tested for continuity. Electrical issues are never easy to find unfortunately. I would firstly check the resistance up the signal wire and compare it to the resistance of the signal wire from pump 1. The resistance should be almost the same. Do the same with the V+ and gnd wires. Next you can test for continuity again and pull/tug the wiring harness to see if the continuity disappears. This may give you a rough idea the location of the fault. Out of interest, can you get the machine to fault at will? As in, if your testing will the 2 speed travel start and stop working during testing? One thing you could try is tap into the signal wire right at the multiplug at the controller and monitor the voltage. If you have both travel levers fully forward/reverse i'd expect to see a lower voltage reading. If the voltage goes high or reads 0 then that's the fault. For reference, the pump delivery pressure sensors need to read a low reading( it will fluctuate around 1-2v depending on pump load), the pump control sensors on the regulators should read a high voltage( around 4.5v) Another thing, is the auto idle working as it should? Will it decrease with the levers in neutral and increase when using the travel lever? I hope this is helping, i'd hate to think i'm leading you astray and it's a totally different fault. Also, i'd normally use MPDr to diagnose this. The checks with voltage checking is something i wouldn't normally do as i can see all the proper readings with MPDr. As for the local dealer. It all depends on the quality of engineer that looks at the machine. If he's had plenty of experience then he should find it without issue. Especially if he's using diagnostic equipment. Hope this info helps.

 

[mark18mwm]

thanks for the new information again. The info on readings will be a real help, I was wondering what everything was supposed to read and I cant seem to find the stuff I need in the service manual. Unfortunately we can't make it duplicate the travel problem at will, totally random. i'm not sure how the auto idle is working. I guess I never paid attention when I got in it. I think I would have noticed it not working but I might have missed it. the machine is back out working today, hopefully I can get a full day to look at it soon. This has turned into a personal challenge for me that I will conquer, some how, some way, some time! Me and that machine are at war. HaHa.

 

[garyw]

Haha, i'm sure you'll get to the bottom of it soon. Just a note on the auto idle. Make sure the auto idle goes back to full revs when the travel lever is moved. Then you know the travel pilot pressure sensor is ok. And make sure it cuts down to idle and the revs raise again when the front attachment control levers are moved, then you know the front attachment pilot sensor is ok. I'll keep an eye out on here for any future update.

 

[Brandon250]

Hey guys i know this is a little old thread but have a zx160lc doing the exact same thing only for mine is pritty much at fault all the time and bugging me crazy have the machine on a work site 50 hrs a week and its driveing me crazy i thought for the last month or two that it had been fuel issue as it started when i had a fuel issue and been back and forth since more at fault then not tho how exzatly can i clear the code and by chance did you figure out what your issue was on yours ?