New Holland ENG 1002 – ENGINE: Coolant Temperature High

The engine coolant temperature has exceeded the safe operating threshold. When this occurs while the engine is running, the system will trigger a critical audible alarm, the STOP indicator will illuminate, and the left-hand display on the dashboard will flash. If left unaddressed, the engine control system may derate engine power or force an engine shutdown to prevent catastrophic damage.

• TM Series (TM120 through TM190)
• T5040-T5070
• TS Series (TS115A)
• T5 Series
• T6 Series
• T7 Series
• T8 Series
• TC Compact Tractors (TC33DA, TC34DA, TC40DA)
• CNH Backhoes (B90B, B95, LB75.B)
• Skid Steer Loaders (L180-L230)
• Compact Track Loaders (C185-C238)
• Telehandlers (LM series)
• Wheel Loaders (LW80, LW80.B)

1. 1

   Ensure the engine is completely cool. Check the coolant level in the overflow bottle and radiator.

2. 2

   Inspect the radiator fins and front grille for debris, dust, or chaff that could be blocking airflow.

3. 3

   Inspect the radiator cap and pressure relief valve, check for coolant leaks at hoses, and verify the engine cooling fan is operating correctly.

4. 4

   Ensure the key-switch is OFF. Remove the connector from the Engine ECU/DCU and the coolant temperature sensor. Check the pins for damage, corrosion, or backing-off. Test and record the resistance values of the sensor to see if it is shorted or out of specification.

5. 5

   If the sensor and wiring are good, the issue may be a mechanical failure such as a failed thermostat (water temperature regulator) or a faulty water pump.

1. 1

   Cool Down

   Allow the engine to cool completely and relieve the cooling system pressure by carefully removing the radiator cap.

2. 2

   Locate the Sensor

   Locate the coolant temperature sensor, which is typically threaded into the engine block or thermostat housing where coolant leaves the engine.

3. 3

   Disconnect

   Unplug the electrical wiring harness connector from the sensor.

4. 4

   Remove the Sensor

   Unscrew the old sensor. Have a catch pan ready, as you will lose a small amount of coolant during this step.

5. 5

   Install the New Sensor

   Thread the new sensor into place. (Note: Many OEM brass sensors require thread sealant if not pre-applied to prevent galvanic corrosion and leaks).

6. 6

   Reconnect and Refill

   Reconnect the wiring harness securely to prevent intermittent gauge problems caused by engine vibration. Top off the engine coolant to replace any lost fluid.

7. 7

   Clear Codes

   Clear the DTC from the diagnostic memory. On some dashboards, this can be done by holding down the digit set button during the key 'ON' self-test sequence, or alternatively use a compatible CAN-Bus diagnostic scan tool.