Case IH U55 – Central Control Unit (CCU): PTO started too early

The PTO is turned on or engaged while the system is attempting to complete the PTO twist sensor calibration procedure.

• Case IH Puma 140
• Case IH Puma 165
• Case IH Puma 180
• Case IH Puma 195
• Case IH Puma 210
• Case IH Puma 225 CVX
• Case IH Magnum MX210
• Case IH Magnum MX230
• Case IH Magnum MX255
• Case IH Magnum MX285

1. 1

   Verify PTO Status: Ensure the physical PTO switch in the cab is turned to the OFF position.

2. 2

   Check Switch Functionality: Access the tractor's 'H' diagnostic menu (specifically menu H5) to check the live function and state of the PTO switch.

3. 3

   Inspect Wiring: Check the electrical connections and wiring harness running from the PTO switch to the electronic control module to ensure there are no shorts causing a false 'ON' signal.

1. 1

   Abort and Reset

   Turn the PTO switch off and clear the active error.

2. 2

   Repeat Calibration

   Restart the PTO twist sensor calibration procedure from the beginning, ensuring the PTO remains off for the duration of the test.

3. 3

   Test the Switch

   If the U55 code immediately returns despite the PTO being physically off, the module is receiving an incorrect signal. Use the H5 diagnostic screen to confirm if the switch is stuck closed.

4. 4

   Replace Components

   If the switch fails the diagnostic check or the wiring connector is damaged, replace the PTO switch.