New Holland ENG 3375 – Engine Controller (Engine ECU / EDC): Constant Engine RPM Increase / Decrease Switch - Short circuit to Battery

A malfunction in the Engine Speed Management (ESM) system where the switch that allows the operator to set, increase, or decrease a constant engine RPM is sending a voltage signal to the controller that is too high (shorted to a 12V power source).

• New Holland T8.xxx Series
• New Holland T6000 Series (T6010, T6020, T6030, T6040, T6050, T6060, T6070)
• New Holland CR9090
• New Holland CX8080 Elevation
• New Holland CX8090 Elevation

1. 1

   Visually inspect the Constant Engine RPM switch (on the right-hand console, armrest CommandArc, or transmission control joystick) for physical damage, sticking buttons, or liquid intrusion.

2. 2

   Trace the wiring harness from the switch to the Engine ECU. Look for chafed insulation, pinched wires, or melted areas that could cause the signal wire to short against a 12V power wire.

3. 3

   Disconnect the switch, turn the key ON, and use a multimeter to check the signal wire on the harness side. If it reads 12V while disconnected, the short to battery is in the wiring harness.

4. 4

   Test the switch itself for internal shorts by checking resistance across the terminals while toggling the switch.

5. 5

   Use on-board diagnostics (e.g., H9 Voltmeter diagnostic menu on T6000 series) to verify the operation of switch circuits. Perform a 'wiggle test' on the wiring harness while watching the display for sudden voltage spikes.

1. 1

   Disconnect Power

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

2. 2

   Access the Switch

   Remove the retaining screws and carefully pry up the trim panel on the right-hand console or armrest to access the underside of the switch bank.

3. 3

   Disconnect the Switch

   Unplug the electrical connector from the Constant Engine RPM switch.

4. 4

   Address the Fault

   If the switch failed internally: Depress the retaining tabs on the sides of the switch body and push it out of the console panel. Snap the new OEM switch into place. If the harness is shorted: Locate the damaged section of the wiring harness. Cut out the fused/damaged wires and splice in new wire using marine-grade heat-shrink butt connectors, or replace the affected sub-harness.

5. 5

   Reassembly

   Reconnect the electrical connector to the switch and reinstall the console trim panels.

6. 6

   Clear Codes and Test

   Reconnect the battery. Turn the key ON and clear the inactive fault codes. Start the engine, set the hand throttle to 1000 RPM, and activate the Engine Speed Management switch to verify it holds and adjusts the RPM without triggering the ENG 3375 code.