Tractor Repair: Pto on mx120, jumper wire, fuse box

Question
Pto shuts off when you change rpms quick. Pto error codes are 15 and
62. Any clues?

Answer
  Code 15 is for the pto switch.  There are 2 types of switches.  Early tractors have a switch activated by a small lever.  Later ones have the knob that you lift up.  On the early style if the pto turns on, the switch is good.  On the later style if the pto turns on, the switch is probably good, but if the pto shuts off by barely touching or wiggling the switch while it's on, replace it.

  Code 62 means that either the pto is overloaded (slipping), or there is a bad frequency signal from the W terminal of the alternator.  If this problem occurs with no load on the pto, then obviously it is not slipping and it is related to the alternator signal.  If it does it only under load, then the pto clutch may be worn out and slipping.  Sometimes it can be a poor connection where the wire attaches to the W terminal of the alternator, and sometimes the alternator itself is bad even if it still charges the battery.  The frequency signal from the alternator is how the pto controller determines the engine speed.  If the engine speed and pto speed don't match correctly, it shuts the pto off.  If the tachometer also does not work correctly, there is definitely a problem with the alternator signal.  MAKE SURE THE BELT IS TIGHT AND NOT SLIPPING! In order for the controller to calculate the correct match, you need to configure the pto speed to the engine speed.  To do this, pull off the left side panel of the dash, and put a jumper wire between the two terminals to the right of the fuse box.  Start the tractor and set the engine speed to 1000 rpm, and the green pto light will flash a steady pattern of 3 short flashes.  Turn on the pto switch and it will calculate the speed match.  When it's done, the light will flash a steady pattern of 4 short flashes.  Turn off the switch and stop the engine, remove the jumper wire and you're done.