New Holland NH 3126 – Engine Controller (EDC / Engine ECU) or Armrest Controller (ADIC / ARU): Hand Throttle potentiometer 1 high error

The control module is receiving a voltage signal from the primary channel of the hand throttle potentiometer that exceeds the maximum allowable threshold (typically indicating a short to power, an open ground circuit, or an internal failure of the potentiometer itself).

• T4
• T5
• T6
• T7
• T8
• T9
• TG
• TJ
• T5.95
• T5.115
• T8.xxx
• T7030
• T6080
• CR9090
• CX8080
• CX8090
• Magnum
• Magnum 215
• Magnum 235
• Magnum 245
• Magnum 340
• MX
• Steiger

1. 1

   Inspect the wiring harness from the hand throttle assembly in the cab/armrest down to the main cab bulkhead connector for chafed wires, pinched harnesses, or corrosion.

2. 2

   Using a multimeter, check the 3-wire connector at the hand throttle potentiometer to verify the 5V reference supply is present.

3. 3

   Verify the ground circuit has continuity to the chassis/ECU ground (an open ground will cause the signal voltage to default high).

4. 4

   Check the signal wire for a short to a 12V power source.

5. 5

   Back-probe the signal wire while slowly moving the hand throttle from idle to full throttle. The voltage should sweep smoothly without spiking or dropping out. If stuck high, the potentiometer is internally shorted or ground is lost.

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Throttle Assembly

   Remove the plastic trim panels or armrest console cover to expose the hand throttle lever mechanism.

3. 3

   Disconnect

   Unplug the electrical connector from the hand throttle potentiometer.

4. 4

   Remove

   Remove the retaining screws or clips holding the potentiometer to the throttle lever pivot assembly. (Note: On some models, the potentiometer is integrated into the throttle assembly and the entire unit must be replaced).

5. 5

   Install

   Install the new potentiometer or throttle assembly and secure the mounting hardware.

6. 6

   Reconnect

   Plug in the electrical connector and reassemble the armrest/console trim.

7. 7

   Calibrate

   Reconnect the battery. Turn the key on. You will likely need to perform a throttle calibration procedure via the tractor's instrument cluster (ICU) or a diagnostic service tool so the ECU learns the new minimum and maximum voltage values for the new sensor.