Case IH 519010-07 - UCM – UCM: Front suspension center position not changing

This fault indicates that the system is commanding the front axle suspension to move (either during active ride control or during a calibration routine), but the front suspension position sensor (a rotary potentiometer) is not registering any physical change in the axle's position. This can be caused by a failed position sensor, a disconnected or broken sensor linkage, mechanical binding of the axle, or hydraulic pressure issues preventing the cylinders from moving.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series (Models 250, 280, 310, 340, 380, 400)

1. 1

   Inspect the Sensor Linkage: Visually inspect the rotary position sensor located above the front axle. Ensure the mechanical linkage connecting the sensor arm to the axle is intact, not bent, and securely attached.

2. 2

   Test the Position Sensor: Use a voltmeter to test the potentiometer. The voltage should change smoothly without dropouts as the sensor arm is manually swept. If the voltage is stuck (e.g., reading below 740mV or above the expected limit), the sensor is faulty.

3. 3

   Check for Accompanying Codes: Look for related UCM voltage codes like 519010-03 (Position sensor voltage high) or 519010-04 (Position sensor voltage low). Also, check for piston/rod pressure sensor codes (e.g., 519008, 519009, 145, 150), which would indicate the suspension isn't moving due to a hydraulic fault rather than a position sensor fault.

4. 4

   Verify Accumulator Pressures: Ensure the front suspension accumulators are not overcharged. Case IH accumulator charge pressure should typically be between 856–899 PSI. Overcharged accumulators (e.g., 1700+ PSI) can cause the suspension to lock up and fail to move during calibration.

1. 1

   Resolve Mechanical/Hydraulic Binding

   If the accumulators are overcharged, bleed the nitrogen charge down to the recommended Case IH specification (856–899 PSI). Ensure the front suspension swivel pins are well-lubricated and not seized.

2. 2

   Replace the Sensor

   If the position sensor fails the voltmeter test or has internal faults, disconnect the wiring harness, unbolt the sensor from its mounting bracket above the front axle, and install the new rotary position sensor.

3. 3

   Reconnect Linkage

   Attach the mechanical linkage to the new sensor arm, ensuring it has full range of motion without binding.

4. 4

   Perform Suspension Calibration

   After replacing the sensor or adjusting pressures, you must recalibrate the front suspension. Park the tractor on a flat, level surface and ensure it is completely stationary. Initiate the Front Suspension Calibration via the AFS Pro 1200 monitor or the Electronic Service Tool (EST). The UCM will automatically cycle the suspension through its maximum and minimum heights to learn the new sensor voltage limits.