Case IH 2622 – ZTC: Hydrostatic unit speed sensor (N_Hyd1) is shorted to ground

The control module is receiving 0 volts on the sensor's signal circuit, indicating that the signal wire is either physically touching a grounded metal component (chassis/transmission case) or the sensor has failed internally and shorted its own circuit.

• Steiger T4B
• Puma CVX
• Maxxum CVX
• Optum CVX
• Magnum CVX

1. 1

   Inspect the wiring harness running from the ZTC (Transmission Controller) to the N_Hyd1 sensor for chafed wire insulation, pinched wires, or melted loom that could cause the signal wire to touch the tractor chassis.

2. 2

   Perform a sensor isolation test by disconnecting the electrical connector at the N_Hyd1 sensor and using a digital multimeter to check for continuity between the sensor's signal pin and the sensor body (ground). If continuity exists, the sensor is internally shorted.

3. 3

   Perform a harness short test with the sensor disconnected by measuring the resistance between the signal wire on the harness side and the chassis ground. Continuity indicates a short in the wiring harness.

4. 4

   Inspect the sensor and harness connectors for moisture, corrosion, or bent pins that could bridge the signal and ground circuits.

1. 1

   Disconnect Power

   Disconnect the negative (-) battery terminal to prevent electrical spikes during repair.

2. 2

   Locate the Sensor

   Locate the N_Hyd1 speed sensor on the hydrostatic unit section of the CVT transmission housing.

3. 3

   Remove the Sensor

   Disconnect the wiring harness. Remove the sensor mounting screw/bolt (typically a hex or Torx bolt).

4. 4

   Extract and Clean

   Carefully pull the sensor straight out of the transmission housing. Clean the mounting port to ensure no dirt or debris falls into the hydrostatic unit.

5. 5

   Install the New Sensor

   Lubricate the O-ring on the new sensor with clean transmission fluid. Insert the sensor into the port until it seats fully.

6. 6

   Torque to Spec

   Install the mounting screw (standard torque for hydrostatic speed sensors on these units is generally around 9.5 N·m / 7.0 lb-ft).

7. 7

   Reassemble and Clear Codes

   Reconnect the sensor harness and the battery. Turn the key on and use a diagnostic tool to clear the ZTC fault codes.

8. 8

   Test Drive

   Operate the tractor to ensure the transmission shifts smoothly and the 2622 fault code does not return.