Case IH 4558 – EHR (Electronic Hitch Regulation) Controller or ATC (Armrest Tractor Controller): Rear EHR control no.3 – not calibrated

The Electronic Hitch Regulation (EHR) / Electronic Remote Valve controller has lost the calibration values for the #3 rear remote valve, or the calibration was never successfully completed. The system's computer does not know the exact electrical values for the lever's neutral, full extend, full retract, or float positions. As a failsafe, the tractor will typically lock out the #3 remote valve and display a warning light.

• VESTRUM CVX
• Case IH Magnum Series (e.g., MX series, 235–340)
• Case IH Steiger & Quadtrac Series (e.g., 350–600)
• Case IH Puma Series
• Case IH Maxxum Series

1. 1

   Check for hard electrical faults (codes 4178 or 4179) which indicate a wiring or hardware failure rather than a calibration loss

2. 2

   Inspect the armrest lever to verify the #3 remote lever physically returns to the center (neutral) position smoothly

3. 3

   Inspect the EHR control valve wire harness at the rear of the tractor for rubbed wires or corrosion at the connectors

1. 1

   Perform an EHR Lever Calibration

   Enter the tractor's diagnostic/calibration menu (often the 'H' menu). Navigate to the EHR / Armrest calibration section. Follow the on-screen prompts to move the #3 lever through its full range of motion (pull fully back, push fully forward, return to neutral). Turn the ignition key to OFF and wait at least 10 to 30 seconds before turning the tractor back on so the controller can save the new calibration values.

2. 2

   Replace the Armrest Potentiometer

   If the tractor refuses to calibrate (e.g., it constantly tells you to 'move EHR to neutral' when the lever is already centered), the potentiometer inside the armrest switch has failed. Open the armrest console and replace the specific SCV lever module.

3. 3

   Replace the Rear Valve Pilot Head

   If the armrest lever calibrates successfully but the remote still locks up under load and throws codes, the electronic pilot head (actuator module) mounted directly on the rear remote valve is likely failing and must be replaced.