Case IH 5027 (1883.03) - DEC – Transmission Control Module (TCM), Armrest/Cab Controller (ATC), or RPTO control system: Rear Power Take-Off (RPTO) Speed Sensor - Open Circuit or Short Circuit to High Voltage

The system has detected an open circuit or short circuit to high voltage (Vbat) on the Rear Power Take-Off (RPTO) Speed Sensor. The control module is not receiving a valid rotational speed signal from the rear PTO shaft/clutch because the wiring is physically broken/disconnected (open) or the signal wire is improperly grounding out to a power source (short to high voltage).

• VESTRUM CVX
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 225
• Magnum 235
• Magnum 245
• Magnum 250
• Magnum 260
• Magnum 275
• Magnum 280
• Magnum 290
• Magnum 305
• Magnum 315
• Magnum 340
• Magnum 370
• Magnum 380
• MX180
• MX200
• MX210
• MX220
• MX240
• MX270
• MX285
• MX305
• Maxxum 100
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Puma 115 and up
• Farmall 85C
• Farmall 95C
• Farmall 95U
• Farmall 105C
• Farmall 105U
• Farmall 115U
• Steiger 350 to 600 HP

1. 1

   Locate the RPTO speed sensor on the rear transmission/PTO housing and visually inspect the 3-pin electrical connector and wiring harness for physical damage, corrosion, or loose pins.

2. 2

   Disconnect the sensor and use a multimeter to check for continuity between the sensor harness connector and the TCM/ATC module to rule out a broken wire (open circuit).

3. 3

   With the key ON (engine off), test the signal wire at the harness for unexpected battery voltage (Vbat) to confirm a short to high voltage.

4. 4

   If the wiring harness tests good, the internal circuitry of the Hall-effect/magnetic speed sensor has likely failed open and the sensor itself must be replaced.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the RPTO speed sensor on the rear PTO housing/transmission block.

3. 3

   Disconnect

   Unplug the 3-pin electrical connector from the sensor.

4. 4

   Remove the Sensor

   Remove the retaining bolt holding the sensor in place. Carefully pull the sensor straight out of the housing. Have a shop rag ready, as a small amount of hydraulic/transmission fluid may weep from the port.

5. 5

   Clean and Prep

   Wipe the mounting surface clean of dirt and debris to ensure the new sensor seats flush.

6. 6

   Install New Sensor

   Lubricate the O-ring on the new sensor with a small amount of clean transmission fluid. Push the sensor into the port and tighten the retaining bolt to OEM torque specs.

7. 7

   Reconnect

   Plug the electrical connector back into the sensor, ensuring the locking tab clicks into place.

8. 8

   Test

   Reconnect the battery, start the tractor, and engage the rear PTO. Verify that the fault code 5027 is cleared (or clear it manually via the cab monitor/diagnostic tool) and that the PTO RPM is accurately displayed on the instrument cluster.