Case IH 1026 – Hitch Control Module (CCU), Electronic Draft Control (EDC), or Armrest Controller: Position control potentiometer - signal too high

The control module is receiving a voltage signal from the hitch position control potentiometer that exceeds the normal operating parameters. This condition is typically caused by a damaged potentiometer, an internal short circuit, or a wiring harness short to a positive voltage source (+Ve).

• Puma/Mid Range Magnum
• Maxxum
• Farmall
• Magnum 7100 series (7110, 7120, 7130, 7140, 7150)
• Magnum 7200 series (7210, 7220)
• Magnum 235-340 (Series 4)
• Puma 150
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Farmall U Pro EP models (e.g., 115U Pro EP)
• MX Series
• TG Series
• CX Series (CX50 - CX100)

1. 1

   Visually inspect the wiring harness and connectors between the position control potentiometer and the Hitch Control Module for pinched wires, corrosion, or disconnected pins.

2. 2

   Check the mechanical linkage or shaft connecting the control lever (or rockshaft) to the potentiometer to ensure it is not loose, broken, or frozen.

3. 3

   Using a multimeter, test the potentiometer resistance (e.g., 4,000-6,000 ohms) and verify the voltage smoothly transitions across its sweep (e.g., 4.85 +/- 0.1V at max height, 0.9-1.1V at min height).

4. 4

   Test the signal circuit for a short to a 12V power source, which is the primary trigger for the 'signal too high' condition.

1. 1

   Power down tractor

   Turn off the tractor and disconnect the battery to protect the electronic control modules.

2. 2

   Access the potentiometer

   Locate the faulty potentiometer. Depending on the fault location, this will either be on the armrest/side console or mounted on the rear hitch rockshaft.

3. 3

   Remove the faulty sensor

   Disconnect the wiring harness connector. Loosen the mounting hardware and carefully detach the linkage/lever from the potentiometer shaft.

4. 4

   Install the new sensor

   Mount the replacement potentiometer. Ensure the lever is tightened securely onto the new potentiometer shaft so it does not slip.

5. 5

   Reconnect and pre-set

   Reconnect the wiring harness. If installing a rockshaft sensor, manually adjust the sensor base so the base voltage reads within the OEM minimum specification (e.g., 0.9 to 1.1 volts at the lowest position) before tightening it down completely.

6. 6

   Perform hitch calibration

   Run the tractor's hitch calibration procedure. Make sure the hitch is free to move all the way between the cylinder's minimum and maximum limits with no load and no physical interference to allow the CCU to learn the new voltage limits.