New Holland 14002 – ICU: Rear P.T.O. Sensor Shorted to Ground

The signal from the Rear Power Take-Off (PTO) speed sensor is shorted to ground. The Instrument Control Unit (ICU) has detected that the sensor's signal circuit has an improper electrical connection to the vehicle's chassis or another ground point, causing a loss of a valid speed signal. This condition prevents the tractor's electronic control system from accurately monitoring the PTO shaft's rotational speed, which can lead to improper operation or complete failure of the rear PTO system.

• T4 Series
• T4.75
• T5 Series
• T5.105
• T6 Series
• T6.140
• T6.175
• T7 Series
• T7.170
• T7.190
• T7.210
• T7.235
• T7.260
• Maxxum Series
• Maxxum 110
• Maxxum 115
• Maxxum 125
• Maxxum 140
• Puma Series
• Workmaster Series
• Workmaster 75
• TM Series

1. 1

   Visually inspect the wiring harness leading to the rear PTO speed sensor for signs of damage such as chafing, cuts, or heat damage. Ensure the connector is clean, dry, and securely connected.

2. 2

   Check for shorts in the wiring harness by disconnecting the sensor and control module connectors, then use a multimeter to check for continuity between the signal wire at the sensor connector and a known good chassis ground. If continuity exists, there is a short in the wiring harness that needs to be located and repaired.

3. 3

   Perform a sensor resistance test by disconnecting the sensor and measuring resistance across its terminals. A reading of zero or near-zero ohms indicates an internal short, while infinite resistance indicates an open circuit.

4. 4

   Inspect the sensor mounting to ensure the proper air gap exists between the sensor tip and the tone wheel (toothed wheel).

5. 5

   Perform a wiggle test on the wiring harness and connector with the PTO engaged (use caution) to check for intermittent faults indicating a loose connection or wire break.

1. 1

   Prepare machine for service

   Ensure the tractor is on a level surface, the engine is off, and the parking brake is engaged. Disconnect the battery before starting any electrical work.

2. 2

   Locate and access sensor

   Locate the rear PTO speed sensor on the rear transmission or axle housing, positioned over the internal PTO drive gear. Remove any protective covers or shields to access it.

3. 3

   Prepare for oil loss

   Place a drain pan and rags under the sensor area, as removing the sensor will likely result in some transmission oil leakage.

4. 4

   Remove faulty sensor

   Disconnect the electrical connector by releasing the locking clip. Unbolt the sensor from the housing using an Allen key or standard socket and remove it.

5. 5

   Install new sensor

   Lightly lubricate the O-ring on the new sensor with clean transmission oil. Carefully install the new sensor, ensuring it is seated correctly, and tighten the retaining bolt(s) to the manufacturer's specified torque.

6. 6

   Reconnect and reassemble

   Reconnect the electrical connector, ensuring it clicks into place securely. Reinstall any protective covers or shields that were removed.

7. 7

   Test and clear codes

   Reconnect the battery, start the tractor, and clear any stored fault codes using the dashboard interface or an electronic service tool. Test the operation of the rear PTO at various speeds to confirm the repair.