New Holland ENG 145 – Engine Controller (Engine ECU / EDC): Coolant Temperature Sensor voltage is too low.

The signal voltage from the engine coolant temperature sensor has dropped below the acceptable threshold. This is almost always caused by a short to ground in the sensor circuit, a damaged wiring harness, or an internal failure (short) within the sensor itself.

• New Holland T4 series
• New Holland T5 series
• New Holland T6 series
• New Holland T7 series
• New Holland T8 series
• New Holland T9 series
• New Holland TM series (TM120 through TM190)
• New Holland TG series
• New Holland CR series (CR8.90, CR9.90, CR9040, CR9060)
• New Holland CX series (CX7080, CX8080)
• New Holland B-Series Backhoes
• New Holland C-Series Skid Steers
• New Holland Wheel Loaders

1. 1

   Visual Inspection: Inspect the wiring harness leading to the Coolant Temperature Sensor (usually located on the engine thermostat housing or cylinder head water jacket). Look for rubbed-through insulation causing the wire to short against the engine block.

2. 2

   Disconnect Test: Disconnect the electrical connector from the sensor. Turn the key ON. If the fault code changes from ENG 145 (voltage too low) to ENG 144 (voltage too high / open circuit), the wiring is fine, and the sensor itself is internally shorted and must be replaced.

3. 3

   Harness Pin-to-Ground Check: If the code remains ENG 145 with the sensor unplugged, the short to ground is in the wiring harness between the sensor connector and the Engine ECU. Use a multimeter to check for continuity between the signal wire and the chassis ground.

4. 4

   Pin-to-Pin Short Check: Verify there is no short circuit between the signal pin and the ground pin inside the harness connector.

1. 1

   Cool Down

   Ensure the engine is turned off and completely cool. Opening a hot cooling system can cause severe burns.

2. 2

   Locate the Sensor

   Find the sensor on the engine's thermostat housing or cylinder head water jacket.

3. 3

   Prep for Spillage

   Place a catch pan directly beneath the sensor area, as some coolant will escape when the sensor is removed.

4. 4

   Remove the Sensor

   Unplug the 2-pin electrical connector. Use a wrench to unthread the old sensor from the metric or NPTF port.

5. 5

   Install the New Sensor

   Thread the new sensor into the port. (Note: Many OEM brass sensors feature pre-applied thread sealant; if yours does not, apply a liquid thread sealant suitable for coolant). Tighten to the manufacturer's torque spec.

6. 6

   Reconnect

   Plug the wiring harness back into the sensor.

7. 7

   Refill and Test

   Top off the engine coolant reservoir to replace any lost fluid. Start the engine, check the sensor threads for leaks, and verify that the dashboard temperature gauge reads accurately and the ENG 145 code is cleared.