Case IH F72 – Transmission Controller: Engine Torque/RPM Sensor Short To Ground

The Engine Torque/RPM sensor measures engine speed and torque by monitoring the flywheel damper spring deflection. The F72 code indicates that the signal wire for this sensor is shorted directly to a ground source, resulting in a loss of valid torque/RPM data.

• MXM
• Case IH MXM 120
• Case IH MXM 130
• Case IH MXM 140
• Case IH MXM 155
• Case IH MXM 175
• Case IH MXM 190
• Case IH Puma Series

1. 1

   Turn the keyswitch OFF and disconnect the battery power

2. 2

   Disconnect the connectors at both the Engine Torque/RPM sensor (Component B32) and the Transmission Controller to isolate the circuit

3. 3

   Visually inspect the wiring harness routing for rubbed-through insulation, pinched wires, or melted loom

4. 4

   Test for a short to ground by setting a multimeter to measure resistance (Ohms). Connect the black lead to a clean chassis ground and the red lead to the sensor signal pin on the harness connector

5. 5

   Evaluate the multimeter reading: continuity (low resistance) indicates the wiring harness is shorted to ground; an open circuit (infinite resistance) indicates the internal circuitry of the sensor itself has failed

1. 1

   Wiring Repair

   If a short is found in the harness, locate the damaged section. Temporarily splice to restore operation (provided wire length is not altered) or permanently replace the affected harness section.

2. 2

   Sensor Replacement

   If the harness is good, remove and replace the Engine Torque/RPM sensor located near the engine flywheel housing.

3. 3

   Transmission Calibration Preparation

   Whenever a transmission sensor is replaced or a mechanical/electrical repair is made, perform an 'H1 Clutch and Synchroniser Calibration'. Warm the transmission oil (between 20°C and 50°C). Apply the parking brake, turn off the A/C, and deselect all electrical/hydraulic services.

4. 4

   Transmission Calibration Execution

   Hold the High and Low range buttons and start the engine. When 'CAL' appears on the transmission display, release the buttons. Set engine speed to 1200 RPM (+/- 100) and follow the on-screen prompts to calibrate the clutches until 'CF' displays.