Case IH 3367 (F-110-02) – Engine ECU (Engine Control Unit / EDC): Coolant Temperature Test Failure

The engine control system has run a logic/plausibility check on the Engine Coolant Temperature (ECT) sensor and the reading is out of the expected physical range. The ECU typically determines this by comparing the coolant temperature reading to the ambient air temperature and engine oil temperature after the machine has been sitting cold.

• VESTRUM CVX
• Case IH Magnum Series
• Case IH Steiger / STX Series
• Case IH Farmall Series
• Case IH Patriot Sprayers

1. 1

   Cold Soak Comparison: Using a diagnostic scan tool, check the live data for Coolant Temperature, Ambient Air Temperature, and Engine Oil Temperature before starting the tractor for the day. All three should be within a few degrees of each other. If the coolant temp is drastically different, the sensor is likely skewed.

2. 2

   Wiring Harness Inspection: Inspect the pigtail connector at the coolant temperature sensor. Look for pushed-out pins, corrosion from coolant intrusion, or chafed wires shorting to the engine block.

3. 3

   Resistance Test: Disconnect the sensor and measure its resistance with a multimeter. Compare the reading to the OEM resistance-to-temperature chart for your specific engine. An open circuit (infinite resistance) or a dead short indicates a failed internal thermistor.

4. 4

   Coolant Level & Condition: Verify the engine coolant is at the proper level and that there are no air pockets in the cooling system, which can cause erratic sensor readings.

1. 1

   Prep the Machine

   Park the machine on a level surface, turn off the engine, and allow it to cool completely to relieve cooling system pressure.

2. 2

   Drain Coolant

   Place a clean drain pan under the radiator petcock. Drain enough engine coolant to drop the fluid level below the coolant temperature sensor port on the engine block/thermostat housing.

3. 3

   Remove the Sensor

   Disconnect the electrical wiring harness from the sensor. Use a deep socket or wrench to unthread the faulty sensor from the block.

4. 4

   Prepare the New Sensor

   Clean the threads in the engine port. If the new OEM sensor does not have pre-applied thread sealant, apply a liquid thread sealant (or Teflon tape) to the threads to prevent leaks.

5. 5

   Install

   Thread the new sensor into the port by hand to prevent cross-threading, then tighten to the OEM torque specification.

6. 6

   Reconnect

   Plug the electrical connector back in, ensuring the locking tab clicks securely.

7. 7

   Refill and Bleed

   Refill the cooling system with the drained coolant (if clean) or fresh OEM-spec coolant. Leave the radiator cap off, start the engine, and let it reach operating temperature to bleed any trapped air from the system.

8. 8

   Clear Codes

   Top off the coolant, install the cap, and use a diagnostic tool to clear the 3367 (F-110-02) fault code. Verify the dash gauge reads correctly.