Case IH 518567-06 - ACM – ACM: EHR valve selector knob voltage low

The voltage signal returning from the EHR valve selector knob potentiometer to the controller has dropped below the acceptable minimum threshold, pointing to a short to ground, a broken wire, or an internal failure of the potentiometer itself.

• MAGNUM AFS Connect
• Magnum AFS Connect Series
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400 Tier 4B / Stage V
• Steiger / Quadtrac AFS Connect Series
• Puma Series
• Maxxum Series

1. 1

   Check for ACM software updates, as bugs in older versions (prior to 1.1.0.0 or 1.2.0.0) can cause erratic remote valve control or false voltage codes.

2. 2

   Inspect the armrest wiring harness and connectors for damage, pinched wires, or bent/dislocated pins.

3. 3

   Verify ACM power and ground (Pin 1 Unswitched B+, Pin 2 Switched B+, and Pin 7 Ground) to ensure proper voltage.

4. 4

   Connect the Electronic Service Tool (EST) and monitor the EHR selector knob status while rotating it to see if the digital status matches physical changes.

5. 5

   Perform a potentiometer pinout test (Terminal 1 High side/Reference, Terminal 2 Sensor line/Signal Return, Terminal 3 Low side/Ground) to check resistance and voltage for a short to ground.

1. 1

   Disconnect Power

   Turn off the tractor key and disconnect the battery ground to prevent electrical spikes during module handling.

2. 2

   Access the ACM

   Remove the covers on the MultiControl armrest console to expose the Armrest Control Module and the integrated switch panels.

3. 3

   Isolate the Fault

   Disconnect the harness connector at the EHR selector knob panel. Measure the voltage on the harness side (Terminal 1 to Terminal 3) with the key ON to ensure the ACM is sending the 5V reference.

4. 4

   Replace the Component

   If the potentiometer has failed internally (which is the most common cause for a hard "-06" low voltage code when wiring is intact), replace the affected armrest control panel/module assembly.

5. 5

   Reassemble and Calibrate

   Install the new armrest panel/ACM, reconnect the harnesses, and restore battery power.

6. 6

   Clear Codes

   Connect the EST, clear the 518567-06 fault code, and verify that the remote valve selector now registers correctly on the AFS Pro monitor or instrument cluster.