Case IH 2079 - UCM – UCM / CCM: Flywheel speed sensor – no signal

The control module is not receiving a valid rotational speed signal from the engine's flywheel. This signal is critical for calculating engine RPM, managing transmission shifting, and operating the Electronic Draft Control (EDC) and clutch systems.

• MAXXUM T4E
• Puma 165
• Puma 170
• Puma 180
• Puma 185
• Puma 195
• Puma 200
• Puma 210
• Puma 215
• Puma 225
• Puma 230
• Puma CVX
• Maxxum 110
• Maxxum 125
• Maxxum Multicontroller
• Maxxum EP Tier 4
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum Rowtrac
• Steiger 485 4WD
• Farmall Cab
• Farmall CVT

1. 1

   Inspect the harness connection to the flywheel speed sensor for open circuits, shorts to ground, or loose pins

2. 2

   Check the sensor tip for physical damage or a buildup of metallic debris that could block the magnetic signal

3. 3

   Verify the physical condition of the torsional vibration damper, as damage can cause erratic or missing signals

4. 4

   Check if the sensor lost its calibration parameters (indicated by related fault code 2124)

1. 1

   Locate the Sensor

   The flywheel speed sensor is typically located on the engine block near the bell housing. Depending on the specific tractor model (e.g., Magnum vs. Puma), it will be mounted on either the right or left side of the engine.

2. 2

   Clear Obstructions

   If necessary, remove the starter motor heat shield or detach the cab heater return pipe to gain clear access to the sensor.

3. 3

   Disconnect Wiring

   Disconnect the 2-wire engine harness electrical connector from the sensor.

4. 4

   Remove the Sensor

   Remove the single retaining screw/bolt holding the sensor in place and pull the sensor out of the housing.

5. 5

   Install the New Sensor

   Lubricate the new O-ring, insert the new flywheel speed sensor, and secure it with the retaining screw.

6. 6

   Reconnect

   Reconnect the electrical harness and reinstall any heat shields or hoses removed during disassembly.

7. 7

   Recalibrate

   Turn on the tractor and use the diagnostic menu to clear the stored error codes. You must perform a transmission/clutch calibration procedure so the UCM can relearn the flywheel torque and speed sensor baseline.