Case IH 1883-04 - DEC – DEC: Rear PTO shaft speed sensor electrical circuit fault voltage below normal

The control unit has detected that the voltage signal returning from the rear Power Take-Off (PTO) speed sensor has dropped below the acceptable operating threshold. This condition is typically caused by a short circuit to ground, a failed sensor, damaged wiring, or a poor connection.

• MAGNUM AFS Connect
• Magnum Series (180, 190, 210, 225, 245, 260, 305, 315, 370)
• Puma Series (115, 180-260 CVX)
• Maxxum Series (100, 110, 115, 120, 125, 130, 140)
• Farmall Series (85C, 95C, 95U, 105C, 105U, 115U)
• MX Series (MX80C to MX110, MX150 to MX305)
• JXU Series (75, 85, 95, 105, 115)

1. 1

   Check overall battery and system voltage. Low system voltage (below 10V-12V) can sometimes trigger false 'voltage below normal' sensor codes.

2. 2

   Locate the PTO speed sensor on the upper side of the rear PTO housing.

3. 3

   Inspect the wiring harness leading to the sensor for chafing, bare wires, or a short to ground.

4. 4

   Disconnect the sensor and thoroughly clean the connector. Check for bent pins, moisture, or corrosion.

5. 5

   Verify the sensor's air gap from the tone wheel inside the housing, as an improper gap can cause signal failure.

6. 6

   Test the sensor output with a multimeter while the PTO is engaged to see if it is generating a steady, accurate reading.

1. 1

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

2. 2

   Locate the rear PTO speed sensor, which is mounted externally on the upper side of the rear frame transmission/PTO housing.

3. 3

   Clean the area around the sensor thoroughly to prevent dirt or oil mist from falling into the transmission housing when the sensor is removed.

4. 4

   Disconnect the electrical wiring harness connector from the sensor.

5. 5

   Unbolt the retaining hardware and pull the faulty PTO speed sensor out of the housing.

6. 6

   Install the new OEM PTO speed sensor.

   Ensure it is seated correctly to maintain the proper air gap from the internal tone wheel.

7. 7

   Reconnect the electrical connector, ensuring it clicks securely into place.

8. 8

   Turn the tractor key to the ON position and use the tractor monitor display or a diagnostic service tool to clear the 1883-04 fault code.

9. 9

   Start the tractor, engage the PTO, and verify that the PTO speed registers correctly on the dash and that the code does not return.