Case IH 18002 – Armrest Controller (ARM): Hand throttle #1 - voltage too high (New Holland Only)

This code indicates that the control module is receiving a voltage signal from the primary hand throttle position sensor (potentiometer) that exceeds the maximum expected threshold. Technically, this is usually caused by a short to a power source (such as a 5V reference or 12V supply), an open ground circuit on the sensor, or an internal failure of the potentiometer itself causing it to output maximum voltage.

• Magnum
• Magnum 235-340
• T7 Series
• T8 Series
• T9 Series
• TG Series
• TJ Series
• T6000 Series
• TM Series

1. 1

   Visually inspect the wiring harness running from the Armrest Controller to the hand throttle potentiometer for chafed wires, pinched harnesses, or exposed copper.

2. 2

   Disconnect the 3-pin connector at the hand throttle potentiometer and check for bent pins, corrosion, or moisture.

3. 3

   Use a multimeter to verify the sensor has a solid ground connection, as an open ground wire will cause the signal voltage to pull high.

4. 4

   Perform a potentiometer sweep test by measuring the signal voltage or resistance while slowly moving the hand throttle lever to ensure the reading is smooth and linear.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the negative battery cable to prevent electrical shorts during disassembly.

2. 2

   Access the Sensor

   Remove the necessary trim panels and covers on the armrest console to expose the internal hand throttle lever mechanism.

3. 3

   Disconnect Wiring

   Unplug the 3-terminal electrical connector from the hand throttle potentiometer.

4. 4

   Remove the Sensor

   Remove the retaining screws or clips that secure the potentiometer to the throttle lever linkage. Carefully slide the old sensor off the mechanical pivot.

5. 5

   Install the New Part

   Align the new potentiometer with the physical linkage of the hand throttle lever and secure it with the mounting hardware.

6. 6

   Reassemble

   Plug the electrical connector back into the sensor and reinstall the armrest console covers.

7. 7

   Calibrate

   Reconnect the battery and turn the key on. Clear the inactive 18002 fault code. Depending on the tractor model, you may need to enter the tractor's H-Menu or calibration mode via the instrument cluster to perform a throttle position calibration so the Armrest Controller learns the new minimum and maximum voltage values.