Case IH 2110 – Transmission Controller (Trans / TCU): FNR Neutral Switch Low Voltage fault

The FNR (Forward-Neutral-Reverse) switch is responsible for communicating the operator's directional commands to the machine. A "low voltage" fault indicates that the control module is receiving a voltage signal from the neutral switch circuit that is below the expected operational threshold. This is typically caused by an open circuit, a short to ground in the wiring harness, or an internal failure of the switch itself.

• Magnum
• Steiger T4B
• Magnum 235 – 340 (Series 4)

1. 1

   Verify the fault code is active.

2. 2

   Inspect the wiring harness and connectors between the FNR switch (located on the FNRP pod / shuttle lever) and the Transmission ECU.

3. 3

   Ensure all connectors are fully seated, not damaged, and that the pins are in the correct position with a tight fit.

4. 4

   Use a multimeter to check the circuit for continuity, looking specifically for an open circuit or a short to ground.

5. 5

   Test the FNR switch itself for proper voltage output before condemning the component.

1. 1

   Disconnect battery

   Disconnect the machine's battery power before servicing electrical components.

2. 2

   Access FNR switch

   Access the FNR switch / shuttle lever assembly (FNRP pod) in the cab.

3. 3

   Disconnect connector

   Disconnect the electrical connector to the FNR switch.

4. 4

   Repair wiring

   If the diagnostic checks revealed a wiring issue (e.g., a short to ground or broken wire), repair or replace the affected section of the wiring harness.

5. 5

   Remove FNR switch

   If the wiring is intact and the switch tested faulty, remove the mounting hardware securing the FNR switch.

6. 6

   Install new FNR switch

   Install the new FNR switch and secure it in place.

7. 7

   Reconnect connector

   Reconnect the electrical connector, ensuring a tight and secure fit.

8. 8

   Reconnect battery

   Reconnect battery power.

9. 9

   Clear codes and test

   Clear the fault codes using an Electronic Service Tool (EST) or by cycling the key, and test the tractor's forward, neutral, and reverse operation to ensure the code does not return.