Case IH 15 – PTO Controller: Erratic, missing, or implausible signal from the PTO engagement lever switch

The controller detects that the PTO switch was either cycled too rapidly, or the magnetic position sensor on the lever-style switch is failing to provide a steady signal. This is most commonly caused by the small round magnet on the side of the lever being covered in debris, damaged, or having fallen off entirely, which disrupts the magnetic field required to actuate the switch.

• MX Maxxum
• Maxxum MX80C
• Maxxum MX90C
• Maxxum MX100C
• Maxxum MX100
• Maxxum MX110
• Maxxum MX120
• Maxxum MX135
• Maxxum MX150
• Maxxum MX170
• Magnum MX180
• Magnum MX200
• Magnum MX220
• Magnum MX240
• Magnum MX270

1. 1

   Visual Inspection of the Magnet: Locate the PTO engagement lever and inspect the small round magnet on the side of the lever. Verify that the magnet is actually in place and hasn't fallen out.

2. 2

   Check for Debris: Inspect the magnet and switch area for a buildup of dirt, straw, or metallic debris. Debris blocks the magnetic field, causing the switch to send an erratic signal to the controller.

3. 3

   Clean the Sensor: Use compressed air to thoroughly blow off the magnet and the switch area.

4. 4

   Check for Secondary Codes: A failing PTO switch will often simultaneously trigger Code 63 (PTO speed sensor fault). Because the bad switch fails to send a steady engagement signal, the controller doesn't sense the speed sensor signal properly, throwing a secondary code.

1. 1

   Clean and Retest

   Before replacing any parts, use compressed air to blow out all straw and dirt from behind the control cover where the PTO lever resides. Cycle the PTO lever normally. If the code clears and the PTO engages, no further repair is needed.

2. 2

   Access the Switch

   If the magnet is missing or the switch is dead, disconnect the tractor's battery. Remove the interior right-hand trim/control cover panels to access the base of the PTO lever and the switch wiring harness.

3. 3

   Replace the Component

   If the magnet is missing, replace the magnet/lever assembly. If the switch is faulty, unplug the electrical connector from the PTO position switch. Unbolt the old switch from its mounting bracket and install the new switch. Ensure it is properly aligned with the lever's magnet path.

4. 4

   Reassemble and Calibrate

   Reconnect the wiring harness and reinstall the trim panels. Reconnect the battery. You may need to perform a PTO reconfiguration/calibration routine via the tractor's diagnostic display to clear the stored faults and teach the controller the new switch's parameters.