Case IH 1079 – Hitch Control Module: Range of the hitch position is not within specification

During the electronic draft control (EDC) or hitch calibration process, the signal voltage returning from the hitch rockshaft potentiometer is outside the expected parameters when the hitch is at the maximum raise position.

• Magnum
• Steiger T4B
• Magnum 7100 series
• Magnum 7200 series
• Magnum MX series
• Magnum 235-340 (Series 4)
• Steiger STX 350-600
• Puma
• Maxxum

1. 1

   Clear stored fault codes and attempt to recalibrate the hitch before replacing any electronic components

2. 2

   Inspect the rockshaft potentiometer linkage for binding in its bushing, which can cause the internal lever to slip out of position

3. 3

   Inspect the wiring harness and connectors between the hitch position potentiometer and the ECU for damage, corrosion, moisture, and tight pin fitment

4. 4

   Perform an ohmmeter test on the disconnected potentiometer (Terminal A to C should be 4,000-6,000 or 9,000-11,000 ohms; A to B and B to C should vary smoothly from 0 to 10,000 ohms)

1. 1

   Free a Binding Linkage

   If the hitch is stuck and the linkage is bound, loosen the clamp bolt on the lever and slip it off the shaft. Remove the enclosure that holds the potentiometer, then disassemble and clean the shaft and bushing. Reassemble and adjust the potentiometer back into the calibration range.

2. 2

   Remove Failed Sensor

   If the potentiometer fails the ohmmeter test, remove the mounting bolts holding the sensor to the rockshaft housing.

3. 3

   Install New Sensor

   Install the new hitch position potentiometer. Ensure the linkage is properly aligned with the rockshaft so that the sensor sweeps correctly as the hitch raises and lowers.

4. 4

   Recalibrate Hitch

   Turn the key switch on and enter the tractor's hitch calibration mode (EDC calibration). Follow the on-screen or manual prompts to set the upper and lower limits. The controller must learn the new potentiometer's voltage range to clear the 1079 code.