Case IH 1883-00 - DEC – DEC: Rear PTO Output Shaft Speed - Data Valid But Above Normal Operating Range

The fault code indicates that the rear Power Take-Off (PTO) output shaft speed sensor is transmitting a valid signal, but the calculated rotational speed (RPM) is exceeding the maximum normal operating limit. This can be caused by a failing sensor sending erratic high-frequency signals, a short in the wiring harness, or an incorrect PTO shaft size configuration.

• MAGNUM AFS Connect
• Magnum Series (180, 190, 210, 225, 240, 255, 285, 305, 315, 380)
• Puma Series (115, 155, 180-260 CVX)
• Maxxum Series (100, 110, 115, 125, 130, 140)
• Farmall Series (85C, 95C, 105U, 115U)

1. 1

   Inspect the wiring harness from the PTO controller to the speed sensor for damaged wires, moisture in the connector, or bent pins.

2. 2

   Ensure the tractor's display is configured for the correct PTO shaft size (e.g., 1-3/8 inch 540 RPM, 1-3/8 inch 1000 RPM, or 1-3/4 inch 1000 RPM) to rule out software configuration errors.

3. 3

   Disconnect the sensor and test it using a multimeter. Standard variable reluctance sensors should read around 450 ohms +/- 20 ohms. Dual-speed sensors should read approximately 3000 ohms (2700-3300 ohms). Infinite or zero resistance indicates internal failure.

4. 4

   Remove the sensor and check the magnetic pickup tip for metal shavings from the PTO clutch or gears, which can cause erratic high-speed readings.

1. 1

   Preparation

   Park the tractor on a level surface, turn off the engine, remove the key, and allow the drivetrain to cool.

2. 2

   Locate the Sensor

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

3. 3

   Removal

   Disconnect the electrical connector. Clean the area around the sensor base thoroughly to prevent dirt from falling into the transmission housing. Loosen the lock nut and unscrew the sensor.

4. 4

   Installation & Adjustment

   Apply a small amount of thread sealant (such as Loctite 5922) to the threads of the new sensor. Manually screw the new sensor in fully until it bottoms out against the internal gear. Once it touches the gear, unscrew it by exactly 3/4 of a turn to set the proper air gap.

5. 5

   Secure

   Hold the sensor in place and tighten the lock nut to approximately 6 Nm.

6. 6

   Reconnect & Clear

   Reconnect the electrical harness. Turn on the tractor, clear the DEC fault codes using the monitor or a diagnostic tool, and engage the PTO to verify the speed reads correctly without throwing the 1883-00 code.