Case IH 2487 (518576.17) - DEC – Transmission Control Module (TCM) / Transmission ECU: Synchro R1-F2 Position Sensor Signal 1 - Open Circuit or Shorted to Ground

The system has detected that the signal circuit from the Synchro R1-F2 position sensor is either experiencing an open circuit (broken wire, disconnected plug, or failed internal sensor track) or is shorted to ground. Because of this electrical fault, the controller cannot determine the physical position of the R1-F2 synchronizer fork, which prevents the transmission from safely engaging or shifting those specific ranges.

• VESTRUM CVX
• Magnum Series (e.g., Magnum 220 Tier 4B CVT/PST)
• Maxxum Series (e.g., MXM120, MXM130, MXM140, MXM155, MXM175, MXM190)
• Puma Series
• Steiger/Quadtrac Series

1. 1

   Inspect the transmission wiring harness and the connector at the Synchro R1-F2 position sensor for rubbed-through insulation, corrosion, or pushed-out pins.

2. 2

   Disconnect the sensor and use a multimeter to verify that the sensor is receiving the correct reference voltage (often 5V or 13.5V depending on the model) and has a solid ground.

3. 3

   Perform a sensor swap test by swapping the suspect R1-F2 position sensor with another accessible synchro position sensor (such as the Fwd/Rev or 5-8 synchro sensor). If the fault code moves to the new synchro circuit, the sensor itself is internally failed. If the fault code remains 2487, the issue lies in the chassis wiring harness or the TCM.

1. 1

   Park and secure machine

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Locate sensor

   Locate the Synchro R1-F2 position sensor on the transmission housing/top plate. You may need to remove cab floor panels or access it from under the cab depending on the tractor model.

3. 3

   Clean area

   Thoroughly clean the area around the sensor to prevent dirt or debris from falling into the transmission housing.

4. 4

   Disconnect harness

   Disconnect the electrical connector from the sensor.

5. 5

   Remove hardware

   Remove the retaining hardware (typically small bolts or a circlip/snap ring) securing the sensor to the synchro shaft.

6. 6

   Remove sensor

   Pull the faulty rotary position sensor straight out.

7. 7

   Install new sensor

   Install the new position sensor, ensuring the rotary tang aligns correctly with the slot on the synchronizer shaft.

8. 8

   Reinstall hardware and reconnect

   Reinstall the retaining hardware and reconnect the electrical harness.

9. 9

   Calibrate transmission

   Crucial Final Step: You must perform a transmission calibration using the tractor's in-cab display monitor (H-Menu) or a dealer diagnostic tool. The TCM needs to learn the new minimum and maximum voltage end-stops for the replacement sensor. The transmission will not operate correctly until this calibration is successfully completed.