Case IH 518422-13 - ACM – ACM: Hand throttle 1 sensor disagreement

The two signal channels coming from the hand throttle are not matching the expected mathematical correlation (e.g., they are not sweeping together properly), indicating a sensor failure, a mechanical linkage issue within the handle, or a wiring fault.

• 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
• Steiger AFS Connect Series
• Quadtrac AFS Connect Series

1. 1

   Check for other active ACM codes, particularly 5V reference codes (e.g., 518422-03 for high voltage or 518422-06 for low voltage). If present, diagnose the power supply circuit first.

2. 2

   Remove the armrest trim and visually inspect the wiring harness leading to the hand throttle sensor for chafed wires, pinched harnesses, or loose connections.

3. 3

   Disconnect the hand throttle sensor and the ACM connectors to check for bent pins, pushed-out terminals, corrosion, or moisture.

4. 4

   Perform a live data sweep test using the diagnostic display or Electronic Service Tool (EST). Monitor Hand Throttle Channel 1 and Channel 2 voltages while moving the lever from idle to full throttle. Both should sweep smoothly; if one drops out or spikes, the sensor is internally faulty.

5. 5

   Verify that the sensor is receiving a steady 5V reference and a solid ground from the ACM.

1. 1

   Power Down

   Turn off the tractor, remove the key, and turn off the battery disconnect switch to prevent short circuits.

2. 2

   Access the Sensor

   Remove the retaining screws for the right-hand armrest console cover to expose the internal throttle and joystick mechanisms.

3. 3

   Disconnect

   Locate the hand throttle assembly and disconnect its electrical harness connector.

4. 4

   Remove the Sensor/Assembly

   Remove the mounting hardware (typically M4 screws) securing the throttle potentiometer or the entire throttle lever assembly to the armrest chassis.

5. 5

   Install the New Part

   Mount the replacement sensor or throttle assembly and tighten the retaining screws.

6. 6

   Reassemble

   Reconnect the electrical harness, ensuring the locking tab clicks into place. Reinstall the armrest console covers.

7. 7

   Calibrate

   Restore battery power. Connect the Electronic Service Tool (EST) and clear the inactive 518422-13 fault code. Perform the hand throttle calibration procedure via the EST or the tractor's AFS Pro display to teach the ACM the new minimum and maximum voltage values.