Case IH 2576 – UCM (User Control Module) or Transmission Control Module (FPS Transmission / Transmission TCU): Wheel speed (transmission output speed) sensor #2 - short to ground or open circuit.

The electronic control module monitoring the transmission output speed (TOS) has detected a critical electrical fault in the circuit for sensor #2. The system is seeing either a broken connection/cut wire (open circuit) or a wire that is improperly touching the machine's chassis/ground (short to ground), resulting in a loss of the speed signal.

• Optum
• Case IH Puma Series (Puma 130 through Puma 240)
• Case IH Steiger Series (STX 350 to 600)
• Case IH Magnum Series (Magnum 180 to 225)

1. 1

   Check the sensor's wiring connector for faults such as moisture, corrosion, or backed-out pins.

2. 2

   Trace the wiring harness from the transmission output speed sensor back to the UCM/Transmission ECM. Use a multimeter to test for continuity (to rule out an open circuit/broken wire) and test for continuity to ground (to rule out a short to ground).

3. 3

   If the wiring harness is intact, test the internal coil of the magnetic pickup sensor for resistance to determine if it has failed internally (open circuit).

1. 1

   Locate the Sensor

   Locate transmission output speed sensor #2, which is positioned directly within the main transmission housing or rear axle housing.

2. 2

   Rectify the Cause

   If the wiring harness is damaged, repair the broken or shorted wire. If the wiring tests good, remove the retaining bolt and extract the faulty speed sensor. Install the new sensor and ensure the integrated index-keyed wire harness plug is securely seated.

3. 3

   Clear the Code

   Once the physical repair is made, use the tractor's diagnostic interface or AFS Pro display to clear the inactive error code from the UCM/Transmission controller.

4. 4

   Test Operation

   Test the system for normal operation by driving the tractor to ensure the transmission controller is receiving a clean rotational velocity signal and that gear shifts/clutch engagements are smooth.