Case IH 1979-13 - UCM – UCM: Spool valve position sensor (transducer) inside rear pilot head #6 not calibrated or lost calibration data

Fault code 1979-13 indicates that the spool valve position sensor (transducer) located inside rear pilot head #6 has not been calibrated or has lost its calibration data. In Case IH Electro-Hydraulic Remote (EHR) systems, the pilot head receives CAN bus messages from the control module to move the remote valve spool to the desired position. The position sensor monitors this movement. If the sensor is not calibrated, the system cannot accurately regulate the hydraulic flow for that specific remote valve.

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1. 1

   Check that the cable harness connections to the pilot head are secure and free of corrosion or damage

2. 2

   Verify that the transducer is properly connected to the test point

3. 3

   Check if the transducer is functioning correctly or if it has completely failed (which is a common cause for losing calibration)

1. 1

   Replace the Pilot Head

   The position transducer is located on top of the valve, and typically, the entire pilot head assembly must be replaced if the sensor fails. Remove the faulty pilot head from the remote valve section and install the new one.

2. 2

   Reassign Valve Addresses

   After installing a new pilot head, you must reassign the valve addresses so the UCM knows which in-cab lever controls remote valve #6.

3. 3

   Connect Calibration Tools

   Connect the special pressure transducer service tool and jumper harness to the valve's test point. This tool monitors the load sense signal pressure and sends it to the computer during calibration.

4. 4

   Run Calibration

   Access the valve calibration channel (e.g., Channel 1 for rear EHR valves) via the tractor's display or diagnostic tool. Follow the on-board prompts to tune the valve for proper function.