Case IH 2018 – Armrest Control Module (ARM) or Electronic Hydraulic Remote (EHR) Controller: Voltage from R2 switch too high

The control module is receiving a signal voltage from the R2 switch that exceeds the maximum expected operating range (typically above 4.5V on a 5V reference circuit). This almost always indicates an open circuit (a broken wire or disconnected plug), a loss of ground (which causes the signal to pull high), or a short to a higher voltage power source.

• Farmall
• Case IH Magnum Series (e.g., 250, 280, 310, 340, 380)
• Case IH Steiger / Quadtrac Series
• Case IH Puma Series (e.g., 185, 200, 220)

1. 1

   Visual Inspection: Access the armrest console and inspect the wiring harness and connector at the R2 switch. Look for backed-out pins, corrosion, or chafed wires.

2. 2

   Ground Check: Use a multimeter to verify the switch has a solid ground connection. An open ground is the most common cause of a 'voltage too high' code.

3. 3

   Voltage Check: Turn the key ON (engine off). Back-probe the signal wire at the R2 switch. If it reads a full 5V or 12V, check the harness for a short to power.

4. 4

   The Swap Test: Because the EHR switches (R1, R2, R3, R4) are often identical, swap the R2 switch connector with the R1 or R3 switch. If the fault code changes to indicate the new switch location (e.g., "Voltage from R1 switch too high"), the switch itself has failed internally. If the fault remains on the R2 circuit, the issue is in the tractor's wiring harness or the Armrest Control Module.

1. 1

   Turn off the tractor and disconnect the negative battery cable.

2. 2

   Remove the Torx/Phillips screws securing the armrest control panel or the specific EHR pod housing.

3. 3

   Carefully lift the panel to expose the underside wiring.

4. 4

   Disconnect the electrical harness from the faulty R2 switch.

5. 5

   Depress the retaining tabs or remove the mounting screws holding the R2 switch in the armrest bezel and pull the switch out.

6. 6

   Snap the replacement switch into the bezel and reconnect the electrical harness.

7. 7

   Reassemble the armrest console.

8. 8

   Reconnect the battery.

9. 9

   Turn the key ON and clear the inactive fault codes.

   Depending on the tractor model, installing a new EHR switch may require you to run the EHR lever calibration procedure via the Pro 700/1200 display so the ECU can learn the new switch's neutral, extend, and retract voltage values.