John Deere 3038E PTO Coil Fault
Yesterday I mowed the grass with my John Deere 3038E and everything worked fine. Today the mower does not engage and shows the failure of the PTO coil on the dash. I have measured the resistance across the pins on the solenoid and it is 8.5 ohms. The test procedure says it should read approximately 5.5 ohms. Is 8.5 ohms close enough? Should I go ahead and replace the PTO solenoid? I hate starting to replace $ 174 parts if I’m not sure it will solve the problem.
Coincidentally I just experienced the exact same problem on a John Deere 3038E.
I followed the troubleshooting procedure in the technical manual. I first measured the voltage across the solenoid valve when the PTO was engaged. It was like 9 volts, but then the manual explains that the controller uses some kind of pulse width modulation to limit current input, so for the moment I assumed that measured 9v instead of 12v was normal.
I pulled out the valve (it is impossible to remove the connector with the valve installed) which took me half an hour to find the right size metric allen key (I have to find a better way to organize them).
The coil resistance was like 8 or 9 ohms instead of 5.5. I have a professional-quality Fluke multimeter, so I trust the measurement. I ran the valve to a 12V source on my workbench and it didn’t make any noise when I applied voltage to it.
I ordered a new one that arrived yesterday. Before installing it I tested it on the bench. There was an audible, palpable thump as the tension was applied. I installed it and the PTO action was restored.