New Holland 18002 – ECU / Armrest Controller: Throttle Control Lever #1 Voltage Too High

The Armrest Control Module (ACM) has detected that the voltage signal from the Hand Throttle #1 position sensor is above the expected maximum threshold. This indicates an electrical fault, such as a short circuit to a power source or an internal sensor failure, causing an abnormally high signal. Because the engine control unit relies on this signal to determine the operator's desired engine speed, this fault can result in a loss of throttle control and cause the engine to default to a preset speed.

• T4.65V
• T4.75F/V
• T4.80F/V
• T4.85F/V
• T4.90F/V
• T4.95F/V
• T4.100F/V
• T4.105F/V
• T4.110F/V
• T4020
• T4030
• T4040
• T4050
• T4060
• T5.95
• T5.105
• T5.110
• T5.115
• T5.120
• T6.120
• T6.125
• T6.140
• T6.145
• T6.150
• T6.155
• T6.160
• T6.165
• T6.175
• T6.180
• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070
• T6080
• T6090
• T7.165
• T7.170
• T7.175
• T7.185
• T7.190
• T7.200
• T7.210
• T7.220
• T7.225
• T7.230
• T7.235
• T7.245
• T7.250
• T7.260
• T7030
• T7040
• T7050
• T7060
• TM120
• TM130
• TM140
• TM155
• TM175
• TM190

1. 1

   Visually inspect the wiring harness leading to the hand throttle assembly for damage, chafing, pinching, or corrosion on the connectors

2. 2

   Check for loose connections between the hand throttle and the main tractor harness

3. 3

   Check for blown fuses related to the armrest controller or engine ECU

4. 4

   Test the hand throttle potentiometer using a multimeter set to DC volts. Identify the three wires (5-volt reference, ground, and signal). Back-probe the signal wire with the key on and sensor connected, then slowly move the throttle from minimum to maximum. Look for smooth voltage increases without sudden jumps, drops, or spikes. A short to the 5-volt reference wire will cause a 'voltage too high' reading

1. 1

   Confirm the Fault

   Use the tractor's diagnostic display or a diagnostic tool to confirm that fault code 18002 is active or stored.

2. 2

   Perform Diagnostic Checks

   Complete the diagnostic checks listed in the section above. If a wiring issue is found, repair the damaged section of the harness.

3. 3

   Isolate the Potentiometer

   If the wiring appears to be in good condition, the potentiometer is the most likely cause of the fault.

4. 4

   Access and Replace the Potentiometer

   Gain access to the hand throttle assembly, which may require removing covers on the armrest console. Disconnect the electrical connector from the potentiometer. Unscrew and remove the old potentiometer from the throttle lever mechanism. Install the new potentiometer, ensuring it is correctly oriented. Reconnect the electrical connector and reassemble the armrest covers.

5. 5

   Clear Fault Codes

   After the repair, clear the fault codes from the control module's memory.

6. 6

   Verify the Repair

   Start the tractor and operate the hand throttle through its full range of motion to ensure it is functioning correctly and that the fault code does not reappear.