Deutz-Fahr L 05 – EHR (Electronic Hitch Regulation): Left Draft Pin Sensor: Short circuit to ground

The draft pin sensor is a magneto-elastic force measurement pin (load cell) located at the connection point of the lower link arms to the tractor chassis. A 'short circuit to ground' indicates that the signal voltage has dropped to near 0V. This condition is usually caused by a severed signal wire, the signal wire rubbing against the tractor chassis and shorting to ground, or an internal failure of the sensor's evaluation circuit.

• Agrotron Series (e.g., MK3, M, TTV, K, X series)
• 5 Series (e.g., 5C, 5G)
• 6 Series
• 7 Series
• 9 Series

1. 1

   Visually inspect the left draft pin sensor wiring pigtail and main harness connector for physical damage, packed mud, or pinched wires.

2. 2

   Disconnect the sensor, turn the ignition ON, and verify that the sensor connector is receiving the correct reference voltage (typically 5V or 10V) and has a solid ground.

3. 3

   Test the signal wire from the sensor connector back to the EHR controller harness for continuity, ensuring the signal wire does not have continuity to the chassis ground.

4. 4

   Temporarily swap the left and right draft pin connectors (if cable lengths allow). If the fault code changes to the Right Draft Pin Sensor, the sensor itself is definitively dead.

1. 1

   Relieve Pressure

   Lower the three-point hitch completely to the ground to remove all tension and weight from the lower link arms.

2. 2

   Disconnect

   Unplug the electrical connector from the faulty left draft pin sensor.

3. 3

   Remove Retaining Hardware

   Remove the locking bolt, snap ring, or retaining plate that secures the draft pin to the tractor chassis.

4. 4

   Extract the Sensor

   Support the heavy lower link arm and slide the draft pin sensor out of the chassis bore. (If it is seized, penetrating oil and a brass drift may be required).

5. 5

   Clean and Prep

   Clean the bore thoroughly to ensure the new sensor will not bind.

6. 6

   Install New Sensor

   Insert the new draft pin sensor. Crucial Step: Ensure the alignment notch or flat edge on the pin is oriented exactly as specified in the service manual. These sensors are directional and must be aligned correctly to measure shear force accurately.

7. 7

   Reassemble

   Reinstall the retaining hardware and reconnect the electrical harness.

8. 8

   Calibrate

   Connect a diagnostic tool (such as Deutz SERDIA or Jaltest) to the tractor. Perform the EHR hitch calibration procedure to teach the controller the "zero-point" (unloaded state) of the new sensor.