New Holland ENG 148 – ENGINE Controller (Engine ECU / ECM): Frequency Throttle Signal shorted low

The electrical signal coming from the frequency throttle (accelerator pedal or hand throttle potentiometer) is registering a voltage or frequency that is below the minimum acceptable threshold. A 'shorted low' condition typically means the signal wire is shorted directly to ground, or there is a complete failure of the sensor causing it to output zero signal.

• New Holland T8000 Series
• New Holland TJ Series
• Machines equipped with 8.3L, 9.0L, or 15L engines

1. 1

   Visually inspect the wiring harness running from the hand throttle/foot pedal assembly to the Engine ECU for chafed wires, pinched harnesses, or melted insulation.

2. 2

   Disconnect the throttle position sensor and the Engine ECU connectors to inspect the pins for corrosion, moisture, or pushed-back terminals.

3. 3

   Use a multimeter to check the sensor ground and 5V reference supply to the throttle sensor to ensure it is receiving power.

4. 4

   Measure the continuity of the signal wire to ground with both ends unplugged. If there is continuity to ground, the wiring harness has a short and must be repaired.

5. 5

   If the wiring tests good, verify the throttle sensor itself, as the internal potentiometer/frequency generator has likely failed and is grounding out the signal.

1. 1

   Disconnect Power

   Turn off the key switch and disconnect the negative battery terminal to prevent ECU damage.

2. 2

   Access the Sensor

   Remove the interior cab trim panels surrounding the affected throttle control (either the right-hand console for the hand throttle or the floorboard for the foot pedal).

3. 3

   Remove the Assembly

   Unplug the electrical connector from the throttle potentiometer. Remove the mounting bolts securing the throttle assembly to the cab structure.

4. 4

   Install New Part

   Mount the replacement throttle sensor/pedal assembly and tighten the retaining hardware.

5. 5

   Reconnect and Calibrate

   Plug in the electrical connector, reconnect the battery, and turn the key to the ON position. Note: Many CNH electronic throttles require a calibration procedure via the tractor's instrument cluster or a dealer diagnostic tool (e.g., EST) to learn the new minimum and maximum throttle positions.

6. 6

   Clear Codes

   Clear the ENG 148 fault code from the Engine ECU and test the throttle operation.