John Deere 000186.15 – MCU / ACU / CCU / PTF: Rear PTO Continues To Turn For Too Long After Turning Main Control Module

The rear PTO continues to rotate for an extended period after the Main Control Module has been turned off. This FMI 15 fault indicates that the PTO speed data is valid but above the normal operational range, pointing to a failure in the system responsible for braking or fully disengaging the PTO clutch.

1. 1

   Visually inspect the PTO linkage for debris buildup, loose components, or broken parts

2. 2

   Check hydraulic fluid level and condition, as low or contaminated fluid affects hydraulically actuated clutches and brakes

3. 3

   Check safety switches (such as the seat switch) to rule out erratic PTO command behavior

4. 4

   Perform a hydraulic pressure test at the clutch and brake ports. When disengaged, there should be approximately 150 PSI at the brake port and zero pressure at the clutch port

5. 5

   Test the PTO control solenoid by listening for a click during engagement/disengagement, measuring coil resistance with a multimeter, or applying 12 volts to verify actuation

1. 1

   Repair PTO brake assembly

   If the PTO brake is faulty, split the tractor to access the brake assembly. Inspect the brake piston, friction material, and the pin that prevents the brake from rotating for wear or damage, and replace as needed.

2. 2

   Replace PTO clutch pack

   If the PTO clutch plates are warped and dragging, split the tractor to access and replace the clutch pack.

3. 3

   Replace PTO solenoid

   If the solenoid is identified as the issue, drain the hydraulic fluid, disconnect the electrical connector and hydraulic lines, unbolt the solenoid valve from the transmission housing, and replace it.

4. 4

   Adjust PTO linkage

   For mechanically controlled PTOs, adjust the clutch linkage by adjusting the length of the operating rod to ensure the clutch fully disengages.