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Issue trying to connect to EX120-2 Computer with USB Cable and DR Zx

Discussion in 'Excavators' started by jefftchase, Jun 3, 2021.

  1. jefftchase

    jefftchase Member

    Joined:
    Aug 22, 2010
    Messages:
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    Location:
    Mount Holly, VT
    I have a EX120-2 and I am trying to connect with a DR ZX version thru a usb cable. Using windows xp and emulator. I worked thru the issues with the com port on the computer, but still can not connect to machine. The lights are flashing red on the pvc and ec (about once every two or three seconds). Trying to diagnosis a issue with the pump going to full stroke and stalled. Already replaced all the wiring in the machine and some of the obivious sensors.

    Does any have a different version of the pc software I could try?
     
  2. mg2361

    mg2361 Senior Member

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    The PVC (pump and valve controller) should be blinking about once every second. If it is the controller is working. If it is a steady light, no light or blinking erratically, then there is an issue.

    I can't help you with DR ZX. I use MPDr. Looking into the diagnostic connector, with the lock tab up, starting at the top left and going clockwise are pins 2, 1, 3 and then 4 (I think??). With the key on you should have 0 volts at pin 1, 0 volts at pin 2 (this is actually connected to frame ground), about 1 volt on pin 3 and 5 volts at pin 4. If it is approximately those values then the issue is with your setup.

    Looking into the 4 pin diagnostic plug and with the key off, short the right side 2 terminals (pins 1 and 3) together with a paper clip or wire, then key on. The PVC will flash codes if there are any. Do not read the flashes on the engine controller, this does not apply to that controller.
     
    Vetech63, RPMex and anuradha like this.
  3. jefftchase

    jefftchase Member

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    Location:
    Mount Holly, VT
    I put a meter on the pin 3 and no volts. I put meter on pin 4 and had 5 volts. 0 volts on 1 and 2 pins.

    I tried shorting the 1 and 3 pins and not difference to flash. Still just flashing 1 red per second.

    Any thoughts? I just replaced the cab harness and the exterior harness. Which fixed a shorting issue or two, but not my issue with pump going to full stroke and stalling (when cold it will operate for about 30 seconds and then slowly stall out). Have in limp mode (flipped plates on bottom of pump). Was hoping to check into the computer diagnostics but stuck here.
     
  4. mg2361

    mg2361 Senior Member

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    All your fuses are good, correct?

    With the key on backprobe (carefully) the displacement solenoid connectors on top of the pump. Measure all 4 pins and report.

    Flip the plates on the bottom back to original position. Then swap the solenoid assemblies on top of the pump. Does the machine change to weak hydraulics?
     
    Vetech63 likes this.
  5. jefftchase

    jefftchase Member

    Joined:
    Aug 22, 2010
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    Location:
    Mount Holly, VT
    I am not get any voltage on these solenoid connectors.

    I flipped the plate and ran the machine. Stalled out, but operate at decent pace and then slowly got bogged down and stalled. I switched the plugs and it went to weak hydraulics.

    I check fuses and they are good (used a test light).

    I checked the no. 2 pump relay and have 26 volts on 1, 2, and 3. 0 volts on 4 and 5.

    I started going down the troubleshooting chart for code 22 (even though I do not have any codes). I checked 104 terminal on the pvc and had 26 volts. I checked 103 and 111 and had 0 volts. I just replaced all the wiring, am I correct in thinking I should replace the pvc. I just opened the pvc and there is nothing burnt on the circuit board. Am I off track?

    upload_2021-6-8_15-21-46.png
     
  6. mg2361

    mg2361 Senior Member

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    If you ground terminal 2 (the one that goes to PVC pin 104) of the pump control relay does the relay click? If so, try running it with terminal 2 grounded. If it runs normally then perform the procedure below.

    1. Cut the Yellow/Green wire connected between PVC connector pin #104 and Pump Control Relay terminal
    #2. Connect the relay side of the wire to a good ground source.

    2. Cut the Blue/White wire connected between Pump Control Relay terminal #1 and the F3 EC Motor fuse
    (5 amp). Connect the relay side of the wire to a switched fuse (such as F10) so the relay only energizes
    when the key switch is "ON".
     
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  7. jefftchase

    jefftchase Member

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    Mount Holly, VT
    The relay clicks. And I now have 24 volts at each of the solenoids. How when I ground it and try to engage hydraulics it still stalls out. I tried swapping solenoids harness and that did not change anything.
     
  8. mg2361

    mg2361 Senior Member

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    Try swapping displacement solenoid valve assemblies. Make sure the connectors are back to original positions after the swap (whatever connector was on the solenoid closest to the engine stays closest to the engine).
     
  9. jefftchase

    jefftchase Member

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    I swapped the solenoids. It still bogged down and shut off. I swapped connectors (closest wire to engine to farthest solenoid) and it would operate like it was in limp mode. If I ground the no 2 terminal on the relay it operate even slower.
     
  10. mg2361

    mg2361 Senior Member

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    To me it sounds like a defective displacement solenoid valve assembly. But to be honest I am a little confused as to whether the wires are in their original position or not?? If they are in there original position (as if you just walked up to the machine for the first time), and the machine works slow after the solenoid swap, then yes a displacement solenoid would be in order.

    Just to be sure the controller is controlling those solenoids when you ground pin 2 of the relay, go to the Deere dealer and purchase the below light (P/N 4283614, about $30). With the light plugged into either displacement solenoid and working the machine you should see the light flicker (it happens too fast to see anything with DVOM). That would indicate the controller is sending a signal to control the pumps. If both solenoids are flickering, then again I would replace one of the displacement solenoid assemblies.

    Maybe @LACHAU could confirm and shed some light into your situation.

    4283614 490E Pump Displacement Test Harness.jpg
     
    RPMex likes this.
  11. jefftchase

    jefftchase Member

    Joined:
    Aug 22, 2010
    Messages:
    9
    Location:
    Mount Holly, VT
    So I switched them back. It performs the same way with solenoids in either position. Bogs down and stalls when yellow wire harness it plugged into solenoid closest to the engine. Slow if I plug yellow wire into the solenoid farthest from engine. If I ground no. 2 on the relay while the yellow wire harness is plugged in the solenoid closest to the engine it will not bogged down and stall. It will perform super slow hydraulics. If take the ground off the no. 2 it will slow speed up the hydraulics and over the course of a minute it will speed up hydraulic and then finally stall. And if I switch the harness it bogs down when the wire closest to the engine is plug into the solenoid closest to the engine.
    upload_2021-6-11_9-20-40.png
    Its the same part number for both solenoids right?

    I ordered the test light today from deere, price is up to 44 dollars now. Will be mid next week before I see it.
     
  12. mg2361

    mg2361 Senior Member

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    Yep. It would have been nice to have a diagnostic tool connected. Otherwise the only course of action is shotgunning parts at it.

    I sent you a PM.
     
  13. JDCrow

    JDCrow Well-Known Member

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    Location:
    Redmond, Or
    I have 2 new solenoids sitting on the shelf if you want them. Just put on conversion kit. JD