Case IH 21: Pto switch cycled too quickly or Magnet on lever style switch damaged, missing or dirty

This fault condition indicates a communication or mechanical failure at the PTO engagement lever. It means that either the operator cycled the PTO switch on and off too rapidly for the system to safely process the command, or the magnetic sensor mechanism on the lever-style switch is failing due to mechanical wear, magnetic decline, or debris blocking the mechanism.

• MX Maxxum
• Magnum MX Series (MX180, MX200, MX220, MX240, MX270)
• Maxxum MX Series (MX80C through MX170)
• Puma series
• Steiger series

1. 1

   Visually inspect the PTO lever and switch assembly for physical damage, such as a cracked housing, a bent lever, or a missing magnet

2. 2

   Check for and clean out any dust, dirt, or metal shavings that may be blocking the magnetic switch from making proper contact

3. 3

   Remove the switch and test it with a Digital Volt-Ohm Meter (DVOM). A good PTO switch should show a resistance reading between 0 and 1.5 ohms. If it reads out of limits, internal contacts are likely damaged

4. 4

   Verify that the tractor is supplying consistent voltage to the switch and PTO solenoid. Check for low voltage or bad ground connections

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical shorts or accidental startups.

2. 2

   Access the Switch

   Remove the right-hand console or instrument panel covers to access the PTO control linkage and wiring harness.

3. 3

   Remove the Faulty Switch

   Disconnect the electrical harness from the PTO switch. Unbolt the switch from its factory mounting points on the control linkage.

4. 4

   Install the New Switch

   Mount the direct replacement switch to the factory points. Critical Step: You must precisely adjust the switch so that it activates exactly when the PTO lever hits the engaged position.

5. 5

   Reconnect Wiring

   Plug the electrical harness back into the new switch and reassemble the console covers.

6. 6

   Perform Safety Interlock Tests

   Reconnect the battery and test the system. Ensure that the engine will not start if the PTO lever is accidentally left in the engaged position. Furthermore, verify that the automatic PTO shutdown works immediately when you leave the operator seat.