Case IH 518557-03 - ACM – ACM: EHR settings adjustment knob voltage high

The EHR (Electro-Hydraulic Remote) settings adjustment knob is an encoder/potentiometer located on the tractor's multicontrol armrest, used to navigate menus and adjust hydraulic flow control settings. A "voltage high" condition typically indicates that the signal voltage returning from this potentiometer to the controller has exceeded the maximum expected threshold. This is usually caused by a short to power in the sensor wiring, an open ground circuit, or an internal failure of the encoder itself.

• MAGNUM AFS Connect
• Magnum 250
• Magnum 280
• Magnum 340
• Magnum 400
• Steiger AFS Connect
• Optum AFS Connect

1. 1

   Visual Inspection: Inspect the EHR settings encoder knob on the armrest for physical damage, sticking, or liquid spills that may have seeped into the console.

2. 2

   Wiring and Connector Check: Access the underside of the armrest console and inspect the wiring harness connecting the encoder to the Armrest Control Module (ACM). Look for pinched wires, chafing, or exposed copper.

3. 3

   Circuit Testing: Disconnect the encoder and use a multimeter to check the connector pins. Verify that the ground circuit is intact (an open ground will cause the signal voltage to pull high). Check the signal wire for a short to a 12V power source.

4. 4

   Configuration Check: Use the Case IH Electronic Service Tool (EST) to verify that the ACM configuration for the EHR flow encoder (Config B/b 5.1) is correct, as incorrect configuration can sometimes trigger false voltage codes.

1. 1

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts while working on the armrest modules.

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts while working on the armrest modules.

2. 2

   Carefully remove the trim panels and retaining screws on the MultiControl Armrest to access the internal Armrest Control Module (ACM) and switch assemblies.

   Carefully remove the trim panels and retaining screws on the MultiControl Armrest to access the internal Armrest Control Module (ACM) and switch assemblies.

3. 3

   Locate the EHR settings adjustment encoder/potentiometer assembly.

   Locate the EHR settings adjustment encoder/potentiometer assembly.

4. 4

   Disconnect the electrical connector from the faulty encoder.

   Disconnect the electrical connector from the faulty encoder.

5. 5

   Pull the plastic knob off the top of the encoder shaft.

   Pull the plastic knob off the top of the encoder shaft.

6. 6

   Remove the retaining nut or mounting screws holding the potentiometer to the armrest panel and remove the faulty unit.

   Remove the retaining nut or mounting screws holding the potentiometer to the armrest panel and remove the faulty unit.

7. 7

   Install the new potentiometer/encoder and secure it to the panel.

   Install the new potentiometer/encoder and secure it to the panel.

8. 8

   Push the knob back onto the new encoder shaft.

   Push the knob back onto the new encoder shaft.

9. 9

   Reconnect the electrical harness, ensuring the connector clicks securely into place.

   Reconnect the electrical harness, ensuring the connector clicks securely into place.

10. 10

    Reassemble the armrest console trim panels.

    Reassemble the armrest console trim panels.

11. 11

    Reconnect the battery, power on the tractor, and use the AFS Pro 1200 display or the EST to clear the fault code and verify that the EHR menus navigate correctly without throwing a new code.

    Reconnect the battery, power on the tractor, and use the AFS Pro 1200 display or the EST to clear the fault code and verify that the EHR menus navigate correctly without throwing a new code.