How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Kevin Your Own Question
Kevin
Kevin, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 729
Experience:  Over ten years of expirence in Ag Electronics and Hydraulics
32685367
Type Your Agriculture and Farm Equipment Question Here...
Kevin is online now
A new question is answered every 9 seconds

JD 7710 PTO engages 5 seconds then shuts off. I replaced the

Customer Question

JD 7710 PTO engages for about 5 seconds then shuts off. I replaced the speed sensor located above the pto shaft but it didn't help. I tried a different solenoid below the hydraulic oil fill cap but that didn't work either.
Submitted: 1 year ago.
Category: Agriculture and Farm Equipment
Expert:  Kevin replied 1 year ago.

You have already replaced the two most common causes of that particular problem so the next step would be to access the CCU controllers stored diagnostic trouble codes to see what code is shutting the PTO back off. The following steps will walk you through the procedure.

  1. Open the fuse panel and put a spare fuse in the port labeled "DIA".
  2. Turn the key to the run position, "DIA" should be displayed on the dash.
  3. Use the turn signal switch as if making a right turn until "CCU" is displayed.
  4. Pull the turn signal switch towards the steering wheel to the flash to pass position and release. This acts as the enter button to access the CCU controller.
  5. Use the turn signal switch as if making a right hand turn to CCU address 001.
  6. Once you reach 001 it will start displaying code numbers followed by the word "END". Once "END" is displayed turn the red warning lamp switch on and back off to clear the stored codes.
  7. Turn the key off and remove the diagnostic fuse, start the tractor and operate the PTO, once the PTO shuts off repeat steps 1 thru 5 and write down the stored code or codes. Let me know what code or codes were set when the PTO shut off and I can tell you what the CCU controller sees as the problem and we can diagnose from there.

Let me know when you have time.

Thanks,

Kevin

Customer: replied 1 year ago.
075
Expert:  Kevin replied 1 year ago.

CCU code 075 indicates that the rear PTO speed is too low. Seeing how you have already replaced the speed sensor this means there is a wiring problem. The PTO speed sensor is a simple two wire hall effect sensor. The easiest item to check is the sensor ground wire, this would be the cc 050 wire. Simply check for continuity to the frame ground at the sensor. The cc576 wire goes through the back of the cab to the CCU controller located under the right side console. Make sure the sensor is fully installed and is not getting held up by the o-ring. Please keep me posted as I will gladly assist you with further diagnostics as needed.

Thanks,

Kevin

Customer: replied 1 year ago.
I could not find discontinuity between the sensor and the ccu controller. Another observation is that the pto rpm on the dash fluctuate between about 400 (in idle) and 0. It will bounce from 400 to 90 to 380 to 20 to 400 to 10 and then stop. Sometimes the rpm will stay steady and the pto will run for a long time (10 minutes). Other times will shut off after 5 seconds.
Expert:  Kevin replied 1 year ago.

It is possible that you simply may have a bad new sensor. The controller will shut the PTO off should it see the rpm too low for too long as it assumes it is slipping. It is also possible that the tone ring that the sensor reads off has come loose and is not consistently staying in line with the sensor. You can pull the sensor out and try to push the tone ring around with a screw driver if need be. Let me know what you are seeing.

Thanks,

Kevin

Customer: replied 1 year ago.
I tried the tone ring, it's secure. I also cleaned off all of the spokes of the tone ring after I first noticed the problem in case any were junked but it didn't make a difference. I think I will try another sensor.
Expert:  Kevin replied 1 year ago.

Sounds good, keep me posted.

Thanks,

Kevin

Customer: replied 1 year ago.
Tried new sensor and the pto has ran without any problems for about 12 hours. Must have been sold a bad new sensor.
Expert:  Kevin replied 1 year ago.

Thats good as we were running out of easy things to check and the symptoms were consistent with a failed sensor. You wouldn't think that a new sensor would be bad but you never know. Hopefully your dealer was willing to warranty the sensor for you.

I'm just glad to hear your back up and running. Keep me posted if there is anything else I can do to help.

Thanks,

Kevin

Expert:  Kevin replied 12 months ago.

Hello,

Just wanted to check in to see if all was still working as it should? If you are still experiencing trouble please let me know. If all is going well and you have a free moment please rate my service.

Thanks,

Kevin

Customer: replied 12 months ago.
I had trouble with the pto again yesterday. Pto speed jumped around again and shut off a couple times before I got it to run continuously. The pto worked fine for about a week running a tub grinder but it looks like it is failing again. Any ideas?
Expert:  Kevin replied 11 months ago.

Did you notice if there were any fine metal shavings built up on the end of the sensor when you removed it? The end of the sensor is magnetic and fine shavings tend to build up on the end which can start distorting the readings. In this case if you do find shavings that would indicate we have a problem as the buildup over such a short period of time should not occur. Second what condition are the pins in the connector at the sensor? If the connection isn't good giving it an intermittent connection it will do just as you describe.

Keep me posted,

Kevin