Case IH R43 – Central Controller (XCM) / EHR Control Unit: CAN Messages Received By The EHR Valve 4 Are Corrupted Or Missing

The system is detecting that the digital signals expected to be received by or transmitted from Electronic Hydraulic Remote (EHR) Valve 4 (typically the #4 rear remote) are either completely absent or the data packets are corrupted.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Maxxum Series
• Puma Series
• CVX Series
• Magnum Series
• Steiger Series

1. 1

   Check for related codes such as R44, R46, or R47 that might pinpoint the issue.

2. 2

   Connect the Electronic Service Tool (EST) to check the AUX controller status and verify if the XCM can see the Valve 4 controller on the network.

3. 3

   Visually inspect the wiring harness running to the rear remote Valve 4 for chafed wires, pinched harnesses, or corroded connector pins.

4. 4

   Verify that EHR Valve 4 is receiving proper unswitched power and a solid ground, as voltage drops can cause the module to drop off the CAN bus.

1. 1

   Disconnect Power

   Turn off the battery disconnect switch before servicing the CAN bus or hydraulic electrical components.

2. 2

   Clean and Reseat Connectors

   Disconnect the electrical plug at EHR Valve 4. Clean the pins with electronic contact cleaner, check for pushed-back pins, and apply dielectric grease before reconnecting.

3. 3

   Test CAN Bus Resistance

   With the battery disconnected, measure the resistance across the CAN High and CAN Low pins at the valve connector. A healthy CAN bus should read approximately 60 ohms. If it reads 120 ohms or open, there is a wiring break between the XCM and the valve.

4. 4

   Repair Wiring

   If a break or short is found in the CAN lines or power supply lines, repair the harness as necessary.

5. 5

   Replace the Valve Head

   If the harness tests perfectly but the code persists, the electronic command unit (head) on EHR Valve 4 has failed internally and must be replaced.

6. 6

   Clear Memory

   Once repaired, use the tractor's H-Menu (specifically the H8 routine) to clear the non-volatile memory (EEPROM). This erases the stored fault codes.

7. 7

   Recalibrate

   Perform the EHR valve calibration procedure using the tractor's display or the EST to ensure the XCM recognizes the new valve parameters.