Case IH 2159 – Transmission / Hydraulic Control Module: Open circuit in the system pressure transmitter circuit

The control module is not receiving a voltage signal from the hydraulic/transmission system pressure transducer. A reading of 0V or an infinite resistance indicates a broken wire, an unplugged connector, or a completely failed sensor internally.

• Steiger T4B
• Steiger / STX Series 4WD Tractors
• Magnum Series
• Puma Series
• Maxxum Series

1. 1

   Visual Inspection: Locate the system pressure transducer on the transmission/hydraulic valve block. Inspect the sensor connector and the wiring harness leading back to the ECU.

2. 2

   Connector Check: Ensure the connector is fully seated. Disconnect it and check for damaged, pushed-back, or corroded pins. Ensure the fit is tight.

3. 3

   Voltage/Continuity Test: Turn the key to the ON position (engine off) and check the sensor connector for the 5V reference voltage and a good ground. Test the signal wire for continuity between the sensor harness connector and the ECU pinout.

4. 4

   Short/Open Verification: Verify there is no break in the wire (open circuit). If the wiring harness has continuity and the 5V reference/ground are present, the fault is isolated to the transducer itself.

1. 1

   Depressurize the System

   Ensure the tractor is turned off, the implement is lowered, and hydraulic pressure is relieved before removing the sensor.

2. 2

   Harness Repair

   If the diagnostic checks revealed a broken wire or damaged connector pin, splice in a new connector pigtail or repair the wire break.

3. 3

   Sensor Replacement

   If wiring is intact, unplug the electrical connector from the system pressure transducer. Unscrew the faulty transducer from the hydraulic manifold/port. Install the new transducer (ensure the integrated O-ring is seated properly) and tighten to OEM torque specifications. Plug the electrical connector back in.

4. 4

   Clear and Test

   Turn the key on, clear the inactive fault codes using the electronic service tool or in-cab display, and start the tractor. Verify that fault code 2159 does not return and that transmission/hydraulic pressures read normally.