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Boom down randomly becomes weak when warmed up - John Deere 490e excavator

joelx777

Well-Known Member
Joined
Apr 1, 2022
Messages
169
Location
Washington State
Thank you all for your help!

My John Deere 490e excavator has an issue where pressing down with the boom can randomly become weak after operating it for 20-30 minutes or so. Usually, pressing down with the bucket on the ground will lift the machine off it's tracks, but when this error occurs the machine will no longer lift up or press down to push dirt. I can still lift the boom up with load on it or push down with no load (not pushing the ground). If I shut the machine down and return to it later, everything works fine, at least for awhile. I am guessing it is a valve that is sticking when it gets hot somewhere?

Here is what my manual says to do in this situation:
Screenshot 2023-08-14 6.30.46 PM.png


My problem is that as a newbie, I am unsure how to do these tasks. I completed an online course in diesel mechanics and have spent 40 hours in a hydraulics course so far. I know the principles, but the actual hands on work is not something I have done enough of, but I am trying to get more experience.

I looked up the proportional solenoid valve referenced (group 9015-15), but all it shows there is how to use a wiring test harness that is no longer made or sold anywhere.

For the pump and valve controller step, I don't have the computer. I saw I can interpret the blinking lights, but haven't had the cover off yet. I asked a gentleman from this forum who posted years ago that he had the software to send it, but have not heard back.

I have no idea how to manually move the control valve spool and variable pressure compensator valves to check for sticking or how to repair these. Group 3360 in the manual is just how to disassemble / reassemble these.

And so on.

I would really appreciate any advice or insight or direction you could provide!

P.S. - I am also considering buying some PSI test gauges, but don't know exactly what to get. My manuals (tm1504 and tm1505) do not specify exactly what I would need as I am guessing that since these manuals were written for JD mechanics, they assume the mechanics have them already.

Also - I ran through the cycle time test in the manual today, the complete results are below... the strange thing is that boom lower operates almost at the new spec whereas most of the other functions operate slower (it's an old machine) near the max spec:

Boom raise spec 3.2 max 4.3 seconds
Actual 4.2

Boom 4 lower spec 2.5 max 3.9 seconds
Actual 2.8

Arm in spec 3.9 max 5.5
Actual 5.2

Arm extend spec 2.6 max 3.6
Actual 3.1

Bucket load spec 2.6 max 3.4
Actual 3.7

Bucket dump spec 1.8 max 2.6
Actual 3?

Swing left or right 3 revolutions from running start 16.4 max 21.7
Actual 11

Propel 20 meters normal speed 21 seconds max speed 13 seconds slow speed 29 seconds
Actual slow 38
Actual normal 20
Actual max 19l

Propel track raised at max speed 3 revolutions from running start spec 14.5 max 19.0
Actual right 21.8
Actual left 20.5 but very shaky and noisy
 

mg2361

Senior Member
Joined
Jul 5, 2016
Messages
5,420
Location
Pennsylvania
Occupation
Equipment Mechanic
Please supply a serial number of the machine. The serial number will determine if it is a -2 or a -3 machine and will make a difference on the information needed.

Next, remove the covers behind the seat to access the controllers. What does the light on the PVC do when the issue occurs? Perform the jumper method to access codes, if any, and post them.

And, for the record, the test harness is still available (see below). Its part number is 4283614. You can also check the proportional solenoid valves with a test light, by backprobing and using jumpers to connect the test light.

4283614 490E Pump Displacement Test Harness.jpg
 

joelx777

Well-Known Member
Joined
Apr 1, 2022
Messages
169
Location
Washington State
Please supply a serial number of the machine. The serial number will determine if it is a -2 or a -3 machine and will make a difference on the information needed.

Next, remove the covers behind the seat to access the controllers. What does the light on the PVC do when the issue occurs? Perform the jumper method to access codes, if any, and post them.

And, for the record, the test harness is still available (see below). Its part number is 4283614. You can also check the proportional solenoid valves with a test light, by backprobing and using jumpers to connect the test light.

View attachment 292416

Thank you very much for your helpful reply! Here are my answers:

My serial number is FF490ES020154. I think this makes me equivalent to the Hitachi EX-120-2, correct? (reference)

-------------------------------------

As best my wife and I can tell from this video starting at 1:16 I made, my error codes on the PVC are as follows:
13 - Engine Speed Sensor (N Sensor) Malfunction (Additional info from another part of the manual:
Diagnostic Computer displays fault code ’13’ only when engine speed is not within specification. Nofault code is displayed if open circuit between N sensor or EC
Check engine speed:
P-mode: 2350 rpm
E-mode: approx. 2150 rpm
L-mode: approx. 1500 rpm
I-mode: 900 rpm)

18 - Failure of Pump and Valve Controller (PVC)

31 - Disconnected Temperature Sensor (T Sensor) and/or wiring harness (Additional info for 31 and 32: The hydraulic oil temperature sensor (T sensor) senses hydraulic oil temperature. If provides the signal for operation of the warm-up circuit. If the T sensor fails, machine operation will be affected by the warm-up function not operating when warm-up switch is pushed.

32 - Short Circuit of Temperature Sensor (T Sensor) and/or wiring harness

34 - Disconnected Boom Up Pilot Pressure Sensor (BPI sensor) and/or wiring harness. (Additional info from another part of the manual:
Fault code ’34’ indicates that the sensing signal
in lower than 0.25 volts. Possible cause may be a disconnect wiring harness between BPI sensor and PVC or an open circuit in sensor.)

Also - I have never reset these error codes, so some may be old? Not sure if the computer deletes old ones automatically. If I did clear them, how long would I need to operate it before checking codes again?

We used these instructions from manual 1504:
1692212340024.png
and here is what the manual says to do for each:
1692212548911.png
1692212575974.png
1692212600440.png

The forum blocks me from adding the last image (only 4 at a time). So here it is copy and pasted:
34 Disconnected Boom Up Pilot Pressure Sensor (BPI sensor) and/or wiring harness 1) Do Retry Procedure B .
2) Check BPI sensor wiring harness and connectors.
3) Replace BPI sensor


------------------

I have a call in to the Pape dealer for the test harness part number 4283614. They say they see it on their side, but it is only called "Bulb". Is that right? Their price is $58.

--------------

I have been looking for the Dr Zx scanner tool and found a couple of options... what would you think is my best bet?
https://www.aliexpress.com/i/2251832779395064.html?gatewayAdapt=4itemAdapt
or
http://www.obd2store.com/hitachi-dr...achi-excavator-diagnostic-scanner-p-2395.html
or
https://www.ebay.ca/itm/231792073401
 

excavator

Senior Member
Joined
Oct 16, 2006
Messages
1,453
Location
Pacific North West
Back in the day I worked on a lot of Deere/Hitachi dash 1,2,3 & 5 but haven't done much on them for quite a few years. The dash 2 machines especially can make you tear your hair out but if you get to the point where you understand them and can work on them you can stay busy. I'll see if I get some time to do a little studying and see if I can refresh the grey matter to remember a few things.
 

joelx777

Well-Known Member
Joined
Apr 1, 2022
Messages
169
Location
Washington State
Back in the day I worked on a lot of Deere/Hitachi dash 1,2,3 & 5 but haven't done much on them for quite a few years. The dash 2 machines especially can make you tear your hair out but if you get to the point where you understand them and can work on them you can stay busy. I'll see if I get some time to do a little studying and see if I can refresh the grey matter to remember a few things.
Thank you! As I mentioned in the first post, I'm a newbie here to mechanic work so even tips and advice you might consider obvious are helpful to me.

My current questions are:

1. The boom lower function is just weak sometimes, but not slow. I copy and pasted the section out of the 1504 manual above talking about a slow boom, but is that the right troubleshooting area to look at?

2. Above I pasted in the error codes with the PVC. I have never reset any codes though (and I'm not sure I am able to without the computer), should I try to do so?

3. I do not own any hydraulic pressure gauges. I saw this one recommended by the farmcraft guy on YouTube... https://a.co/d/0PFhEQf Will this work for me or do I need something else for my machine? I searched for quick coupler in the manuals and there is no hits... Maybe I just need old school standard fittings? I am also not sure what sizes I'll need. What would I look for in the manual to find this or do I have to measure the fittings on the machine somehow?

4. In a previous message I posted a few options for the dr ZX computer deal... Should I buy one of those or something else? The manual references the diagnostic computer almost everywhere so I assume I'll need it if I'm going to be doing more work?

5. What would you do as the next steps in my shoes to troubleshoot and solve this?
 

Jason Klassen

Well-Known Member
Joined
May 29, 2021
Messages
97
Location
Enderby, British Columbia, Canada
Yours would be equivalent to a -2 Hitachi. John Deere has a split at 25000. 24999 and down is -2, 25000 and up is -3.

I would try clearing the codes and running the machine again until the problem appears. Then force it to do the problem a few times so that it will store a code.

Any of those scanners will probably work. You definitely want one that is on a palm pilot or some other device. The ones that are just a disc that you put into your computer don't work.

I have Dr.ZX on a palm pilot and it worked for a while until my "new" pvc computer from china decided to stop communicating with it.
 

joelx777

Well-Known Member
Joined
Apr 1, 2022
Messages
169
Location
Washington State
Thanks John Deere... $0.25 of wire and plastic I paid $36 plus $20 shipping for :(
 

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excavator

Senior Member
Joined
Oct 16, 2006
Messages
1,453
Location
Pacific North West
The lights can be a bit difficult to see in direct sunlight. I've also extended several of mine so that I can take the light into the cab with me, that way I can run the machine and watch the lights without having another person around.
 

joelx777

Well-Known Member
Joined
Apr 1, 2022
Messages
169
Location
Washington State
I tried to follow the fault code reset procedure as described in this forum thread:

https://www.heavyequipmentforums.co...hitachi-120-2-with-pump-control-issues.46788/

"After counseling from RGL (thank you) I was able to get the computer to flash the codes at me. (Jumper wire in both right hand quadrants of the dr zx port) There were quite a few.. Luckily a quick reset of the codes (Start with jumper in socket, shut off for 10 sec, restart remove for 1+ sec then replace) cut the list down to 2, which was much more approachable"

The procedure was a little unclear, I am not sure it worked as I'm still seeing three codes, 31,32,34.

Any advice? The manual's description of resetting fault codes only applies to the diagnostic computer.
 
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