I have a Hitachi EX120-2 and the engine stalls when hydraulic functions are used. Also does anyone know how to short the dr ex plug to access codes thanks
Welcome to HEF dgvanpelt . See the link to an older thread below. Check out Post #14 ,it shows how to short the dr ex plug and enable the self diagnostic which sets a power indicator light flash sequence, (if there are any codes). HeavyEquipmentForums . . I believe the PVC is the bottom controller and EC is the top controller. Ignore the power light on the EC. if there are any codes ,the power indicator light on the PVC will blink in a pattern of long and or short sequence.
Thanks that information will help greatly
when I turn the key on I don't get a flash from the led and when I jump nothing happened ether thanks
Check for any blown fuses. Pay particular attention that fuses #4 and #7 which are PVC back up and PVC power have no higher than 1A fuses installed. High amp fuses can cause some PVC internals to burn up. Screenshot below of fuse box layout from the Operators manual. .
Thank you that was very helpful I checked all the fuses and they all ok they all also have power when the key is on. I accessed a factory shop manual and I checked power to the EC. I have power to pins 39, 24 and ground to pins 25, 38. And I do have ground at pins 100,101 but no voltage at 102,106. on the harness side plug.Hope this picture is readable. Thank you folks so much
Thank you that was very helpful I checked all the fuses and they all ok they all also have power when the key is on. I accessed a factory shop manual and I checked power to the EC. I have power to pins 39, 24 and ground to pins 25, 38. And I do have ground at pins 100,101 but no voltage at 102,106. on the harness side plug.
I was mostly interested if the PVC was being powered up. Follow the manual and see if the PVC terminals have power from the #4 and #7 fuses. Also confirm the grounds at the (4) ground terminals. When jumping the DRex plug , the fault code sequence ( if there are faults ) will be displayed by the lower PVC controller led.
Ok thanks I took the ec off and I didn't see a led on the top of the pvc so I didn't think it had one so it must be on the side or bottom. I will look thanks.
The led on the PVC should be in the top corner, it may be covered with heavy dust.
Sorry I didn't get back sooner i repair Combines and its the busy season. I have 24 volts on fuse 4 and 7 and a i have voltage on pin 37 and 39 on the pvc plug and i found the the led and it does not flash when the key is turn on and with key on and jumper wire in.
Thanks for your help
Before we get too far along , is this a new problem for you ? Any chance the machine has a hydraulic pump mechanical conversion kit installed ? Post a pic showing the top of the hydraulic pump if unsure if a conversion kit is installed.
Ok I will thanks.
There isn't a mechanical conversion kit on it. Would that be better option. It was bought at a sale with that condition. It's a farm service machine so it's not being run regular. thanks
Heres a picture
I prefer to fix the electric problem but if it's a better solution I can put the Mechanical kit on.
I wasn't recommending a conversion kit, just needed to know if one had been installed. If the PVC is not powering up , I believe there is an internal component that is fried. @mg2361 may be able to help with identifying the issue and suggest a possible fix of the PVC.
Ok great what should I do next. I worked for John Deere for 6 years and I do this for living now so I am very familiar with electrical diagnosis. I have the factory shop manual on my laptop.
I actually haven't started to trouble shoot this with the manual yet.
You can remove the PVC and remove the cover. IIRC there is a small internal component that gets fried. I don’t remember much more than that but there are threads here on HEF discussing it.
Outstanding thak you so much
Just to clarify, you checked for voltage at pins 37, 39, and 46 on the bottom controller (PVC)? Did you make sure you have a good connection to ground at pins 38, 47, 101, and 109? If all this checks out, take the top cover plate off the PVC. Look for the the resistor shown below. Does it look burnt like in the picture? If you orient the blinking LED to the top right corner, the resistor will be in the bottom right corner, if I recall correctly.
All the grounds and hot pins check out. I took the cover off and found a burnt spot. I am forwarding a picture. So it definitely needs the PVC. Thanks for all your help.
How is that white resistor?
That resistor is open.
Is it burnt?
No it isn't
Thank you for all your help I am trying read the flashes from the PVC and there is long flashes and short flashes how exactly do i decipher them. Oh I replaced the PVC and now I get flashes when I short the two wires in diag plug
Check your messages.
Hello, I'm new here. I have the same problem. I found the 10 ohm resistor burned out. I need help. If I just change the resistor, will it work?
Welcome to HEF SILVADARIO ! There is most likely a short somewhere in the 5 volt reference circuit which is what burns the resistor. If fuse #7 has anything higher than a 1 amp fuse, then it will fry the new resistor when the short occurs.
Thank you very much for your attention. I will be checking again next week if there is any news I will return here. I really appreciate your help.
Hi, so a changed controller and 2 valve. I checked the error by the lights on the PCV led. The led show's 5, 22, 31(5 short, 2 long and 2 short, 3long and 1 short light)and search in web and manual but nothing. Anyone know what that error can mean? Thanks for listen.
5-? 22- Pump control not normal 31- Disconnected temperature sensor or wiring issue to the sensor.
code #5, Signal from PVC is not transmitted to EC .
Muito obrigado. Vou ter que verificar novamente para descobrir as causas.
Muito obrigado pela ajuda, terei que procurar a causa da falta de comunicação, você tem alguma ideia do que pode ser? O controlador é novo.
@SILVADARIO , Forum rules are that all posts are to be in English. See some code #5 diagnostic info below. . .
Diesel forgive me, I didn't see that the translator was on. I will be back on Monday to analyze the excavator, thank you very much for your help, if one day I can help the community I will be grateful. Thank you very much for the tip and for your time.
Hello everyone, I want to share the progress of the excavator maintenance. I checked all the wires of the connectors mentioned above and they were fine. After much checking, I needed to replace the angle sensor because the voltage did not exceed 2.1 V. Error code 5 disappeared. 31 was a false contact in the sensor, but code 22 remains. When the engine is started while the hydraulic oil is cold, any function that is activated at the end of the engine cylinder stroke continues to stop immediately. However, after the oil heats up, this problem disappears, but the excavator loses power to the point where it cannot move. I removed the PVC controller connector and checked the grounds and they are all in order, but when I checked No. 46, there is no power (+). The fuses are all good. My question is, can I put another wire outside and place it directly in the fuse box or do I have to put it somewhere else? Please, I need help.
Do you have 24V(+) at PVC pin 37 ? The schematic shows a short jumper from PVC pin 37 to PVC pin 46. .
Were you able to adjust the angle sensor to 4.4V as per the angle sensor adjustment procedure in the manual ?
yes Diesel, I have 24v on pin 37, the angle sensor was adjusted but with 4.39v I think it is within tolerance.
Another thing I forgot to mention, when you turn on the excavator, solenoid no. 1 has 24v and no. 2 has 19.8v constantly. And what I understood from the manual is normally inverted and with 24v
The voltage should be the same. The schematic shows a jumper between terminal 1 on Solenoid 1 and terminal 1 on solenoid 2. Replace the jumper.
Ok, I understand Diesel, thank you very much, I'll go there tomorrow to do this. Regarding pin 46, it has already been resolved, it was a connection problem between the wire and the terminal.
Did you gain any performance or were you able to clear code 22 with lack of 24V(+) at pin 46 being resolved ?
Hello, unfortunately not. I suspect that the new PVC controller has a problem. I opened it to check internally and observe all the components and visually they are fine. I suspected the power transistors because without working (only 10 minutes on) it reaches a temperature of 47°C, while the local temperature is around 8°C. It is winter.
I ordered another one from another supplier in China to test.
Hello to all friends and bosses!! I managed to solve the problem, the last problem with the excavator, I replaced the controller I had previously purchased with a new controller, now the excavator is working normally. Conclusion, the solenoid valves had low resistance which caused the original controller to burn out, the original angle sensor was returning at most only 2.2v, I replaced the solenoid valves and the angle sensor, the voltage of pin 46 returned to normal after resolving a false contact between the wire and the connector. And finally, the controller I purchased was not working normally. Many thanks to everyone who helped, Diesel Dave, thank you for your time and dedication, I also want to thank Mr. Makar Samarskiy for his help outside the platform. If you have the opportunity one day, we can have a coffee!!
Thanks for the follow-up. Good info.
Hello Silvadario, Thanks for the followup reply and I'm glad you had sucess. I see you are in Japan and yet you are sourcing parts from China. Being that Hitachi is made in Japan are there not a lot of parts (new or used) in Japan? I bought new EC and PVC aftermarket boards from china with poor results. Was the one you bought from the same supplier or diferent? Who did you get it from?