Case IH 518595-06 - ACM – ACM (Armrest Control Module): Front hitch working position voltage low

This fault code indicates that the signal voltage returning from the front hitch position sensor (potentiometer) has dropped below the acceptable lower limit (typically < 0.2V). This condition is usually caused by a short to ground in the sensor's signal circuit, an open circuit in the 5V reference wire supplying the sensor, an open circuit in the signal wire between the sensor and the control module, or an internal failure of the front hitch position potentiometer itself.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series (Models 180, 200, 220, 240, 250, 280, 310, 340, 380, 400)
• Case IH Steiger AFS Connect Series

1. 1

   Visual Inspection: Inspect the front hitch position sensor, its connector (often designated X395), and the wiring harness routed along the front frame for physical damage, corrosion, or pulled pins.

2. 2

   5V Reference Test: Disconnect the sensor and turn the key ON. Measure the voltage at the 5V reference pin (often the Orange wire) on the harness side. It should read approximately 5.0V. If it reads 0V, trace the wire back to the ACM for an open circuit.

3. 3

   Ground Circuit Test: Check for continuity to ground on the sensor ground pin (often the Brown wire).

4. 4

   Signal Circuit Test: Check the signal wire (often the Green wire) for continuity between the sensor connector and the ACM connector. Test this wire for a short to ground.

5. 5

   Sensor Sweep Test: If the wiring is intact, test the sensor's resistance with a multimeter while manually moving the front hitch linkage (if possible) to check for dead spots or an internal short.

1. 1

   Power Down

   Turn off the ignition and disconnect the battery via the master isolator switch to prevent electrical spikes.

2. 2

   Wiring Repair

   If a broken wire or short to ground was found during diagnostics, repair the harness using OEM-approved sealed splices and heat shrink.

3. 3

   Sensor Replacement

   If the wiring tests good but the sensor is faulty, unbolt the linkage arm connected to the front hitch position potentiometer and remove the sensor from its mounting bracket. Install the new sensor and reattach the linkage.

4. 4

   Power Up

   Reconnect the battery and turn the ignition ON.

5. 5

   Calibration

   A newly installed front hitch position sensor will not work out of the box and will likely trigger a secondary code (such as 9006). Navigate to the tractor's calibration menu via the AFS Pro display or use the CNH Electronic Service Tool (EST) to perform the 'Front Hitch Calibration' procedure. This sets the upper and lower voltage limits for the hitch travel.

6. 6

   Clear Codes

   Clear the inactive 518595-06 fault code from the ACM and test the front hitch through its full range of motion to verify the repair.