Case IH U110 – Armrest Controller Module (ACM) or Tractor Controller Unit (TCU) / Hitch Control Module: Position potentiometer value too low. The hitch was not raised before the height limit control was changed, or the hitch is not raised from the ON to OFF position.

Failure during the hitch calibration process or standard operation. The control module is reading a voltage signal from the hitch rockshaft position potentiometer that falls outside the expected 0-5V range, or the physical hitch did not reach the commanded upper/lower limit.

• Puma/Mid Range Magnum
• Magnum 7110
• Magnum 7120
• Magnum 7130
• Magnum 7140
• Magnum 7150
• Magnum 7210
• Magnum 7220
• Magnum MX series
• Magnum 235-340 models
• Puma 140
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Steiger Series
• Farmall 40
• Farmall 45
• Farmall 50

1. 1

   Ensure the hitch is physically raised (for U110) or lowered (for U111) before changing the height limit control from ON to OFF during calibration.

2. 2

   Inspect the mechanical linkage connecting the rockshaft to the potentiometer for misalignment due to extreme vibration, dirt buildup, or a slipped linkage arm.

3. 3

   Test the 5-volt sensor supply network for low system voltage.

4. 4

   Test the potentiometer resistance. A healthy rockshaft position potentiometer should read approximately 1,000 ohms (± 10%) across pins A to C.

5. 5

   Check the 3-pin connector and wiring harness for continuity, open circuits, or shorts to ground/power.

1. 1

   Secure the Machine

   Lower the 3-point hitch fully to the ground to relieve hydraulic pressure. Turn off the engine and disconnect the battery to protect the 5V reference circuit.

2. 2

   Locate the Sensor

   Locate the hitch position potentiometer, which is mounted on the rear rockshaft/lift arm assembly (or front hitch assembly, if diagnosing a front hitch fault).

3. 3

   Remove the Faulty Sensor

   Disconnect the 3-pin electrical connector. Remove the mounting bolts securing the sensor bracket and carefully detach the rotary mechanical linkage from the rockshaft.

4. 4

   Install the New Sensor

   Bolt the new potentiometer into place. Ensure the mechanical linkage is indexed correctly. (Note: The sensor has 360 degrees of mechanical travel, but the electrical sweep must align with the physical travel of the hitch arms).

5. 5

   Reconnect Wiring

   Plug in the 3-pin connector and reconnect the tractor's battery.

6. 6

   Recalibrate the Hitch

   Perform a hitch calibration cycle using the tractor's diagnostic display. This teaches the Armrest Controller/TCU the new minimum and maximum voltage values for the raised and lowered positions, preventing false U110/U111 codes.