Case IH 37 – Transmission Controller: Bottom of Clutch pedal switch open circuit or bottom of clutch relay is stuck open.

The controller expects a specific closed-circuit signal when the clutch pedal is fully depressed (bottomed out). This code triggers when the controller detects an open circuit in the Bottom of Clutch (BOC) switch wiring, or if the relay that the switch commands is physically or electrically stuck open.

• MX Magnum
• STX Steiger
• Magnum 180
• Magnum 190
• Magnum 200
• Magnum 210
• Magnum 215
• Magnum 220
• Magnum 235
• Magnum 245
• Magnum 255
• Magnum 275
• Magnum 285
• Magnum 305
• Magnum 340
• MX210
• MX230
• MX255
• MX285
• STX 280
• STX 325
• STX 450
• STX 500
• Steiger 500
• Steiger 550
• T8.xxx Series
• TG215
• TG245

1. 1

   Swap the clutch/park relay with a known good relay of the same amperage (e.g., horn or work light relay) to see if the fault clears.

2. 2

   Inspect the transmission and clutch circuit fuses (e.g., Fuse #39 or the specific road travel/clutch circuit fuse) to ensure the relay and switch are receiving power.

3. 3

   Inspect the wiring harness and connectors at the Bottom of Clutch switch for damage, loose pins, or broken wires causing an open circuit.

4. 4

   Monitor the clutch position potentiometer percentage via the diagnostic display. The switch should engage between 3% and 6% (aiming for 4% or 5% is ideal to account for temperature shifts).

1. 1

   Access the Pedal Assembly

   Locate the Bottom of Clutch switch at the base of the clutch pedal linkage inside the cab console.

2. 2

   Remove the Old Switch

   Disconnect the electrical harness from the switch. Remove the mounting hardware (typically M5 lock nuts) holding the switch to the chassis/pedal bracket.

3. 3

   Install the New Switch

   Mount the new switch and loosely tighten the lock nuts.

4. 4

   Adjust the Switch

   Adjust the physical linkage/position of the switch so that it fully depresses (closes the circuit) only when the clutch pedal is at the absolute bottom of its travel. Tighten the mounting hardware.

5. 5

   Perform Transmission Calibration (TRANS SETUP)

   Run the 'Cal Pedal' procedure via the tractor's instrumentation monitor to teach the ECU the new operating range of the clutch pedal. Run the 'Cal Valve' procedure to calibrate the fill current of the master clutch.

6. 6

   Clear Codes

   Clear Fault Code 37 from the system and test drive the tractor to ensure the transmission engages smoothly without the code returning.