Case IH R42 – Central Controller (XCM): EHR Control Unit 4 Active Switch Error

Indicates a malfunction, implausible signal, or communication failure originating from the active switch (usually the in-cab control lever, joystick, or float switch) that commands the 4th EHR valve.

• MXM
• Case IH MXM Series
• Case IH Magnum Series
• Case IH Puma Series
• Case IH Steiger / Quadtrac Series

1. 1

   Check for Accompanying Codes: Troubleshoot all other error codes first (e.g., R43, R44, R47) which indicate a broader CAN bus or power supply issue rather than a failed switch.

2. 2

   Electronic Service Tool (EST) Check: Connect the EST to check the AUX controller status and monitor the live switch state of the EHR 4 lever.

3. 3

   CAN Bus Wiring Check: Carry out a CAN bus continuity and voltage check between the EHR remote valves and the Central Controller (XCM).

4. 4

   Physical Inspection: Inspect the EHR 4 control lever/switch in the cab for physical damage, sticking, or debris preventing it from returning to neutral.

1. 1

   Power Down

   Turn off the tractor key switch and disconnect the battery to prevent false readings or short circuits during testing.

2. 2

   Inspect Wiring & Connectors

   Access the wiring harness connecting the EHR Valve 4 control lever to the XCM. Disconnect the connectors and check for corrosion, bent pins, or moisture. Measure circuit resistance using a multimeter to ensure there are no open or shorted wires. Repair any damaged wiring.

3. 3

   Replace the Switch/Lever

   If the wiring is intact but the EST shows the switch is unresponsive or throwing an out-of-range value, replace the EHR control lever/joystick assembly.

4. 4

   Software Reload

   If the lever is functioning properly but the error persists, reload the software into the central controller.

5. 5

   Module Replacement

   If the system is still inoperative after a software flash, the central controller processor (XCM) must be replaced.

6. 6

   Calibration

   After replacing any potentiometers, PWM solenoid valves, or microprocessors, you must perform the Transmission/EDC Calibration setup procedure to clear the codes and relearn the module.