Case IH 518422-01 - ACM – ACM: Hand throttle 1 internal failure

The sensor or encoder within the hand throttle assembly is sending an erratic, out-of-range, or implausible signal. The system has detected a hardware or circuit failure originating from within the throttle mechanism itself rather than a simple wiring disconnect.

• MAGNUM AFS Connect
• Steiger AFS Connect

1. 1

   Inspect the wiring harness and connectors leading from the hand throttle to the Armrest Control Module (ACM) for any signs of chafing, pinched wires, corrosion, or loose pins.

2. 2

   Check the 5V reference supply and ground to the hand throttle sensor for voltage irregularities.

3. 3

   Perform a signal sweep test using a multimeter or the Case IH Electronic Service Tool (EST) to monitor the throttle output signal for dead spots, drop-offs, or erratic voltage spikes.

4. 4

   Ensure the ACM has the latest software update, as outdated firmware can falsely flag internal component failures.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Disassemble Armrest

   Carefully remove the armrest control panel bezel (surrounding the throttle and multi-function handle) to access the internal components of the armrest. You may need to remove the throttle knobs first.

3. 3

   Disconnect

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

4. 4

   Remove

   Remove the mounting screws securing the hand throttle mechanism to the armrest chassis.

5. 5

   Replace

   Install the new hand throttle assembly and secure it with the mounting screws.

6. 6

   Reassemble

   Reconnect the electrical harness, reinstall the armrest control panel bezel, and reattach the throttle knobs.

7. 7

   Calibrate

   Reconnect the battery. Turn the key on and use the Case IH EST diagnostic tool to clear the 518422-01 fault code. A calibration of the throttle position sensor will likely be required so the ACM can learn the new minimum and maximum voltage thresholds.