Deutz-Fahr 110 – Engine Control Module (ECM) / EMR3 / EMR4: Engine Coolant Temperature Sensor Fault

The Engine Control Module (ECM) has detected that the signal from the Engine Coolant Temperature (ECT) sensor is outside of its expected range. Depending on the specific Failure Mode Identifier (FMI), this indicates either an electrical fault in the sensor or its circuit (such as a short or open circuit), or a genuine engine overheating condition where the coolant temperature has exceeded safe thresholds.

• Agrotron
• Agrotron 110
• Agrofarm
• Agrokid

1. 1

   Visually inspect the ECT sensor, its connector, and the wiring harness leading back to the ECM for chafing, melting, pinched wires, or corrosion.

2. 2

   Check the coolant system to ensure the coolant level is correct and inspect for leaks, a dirty or blocked radiator, and collapsed hoses.

3. 3

   If diagnosing an electrical fault (FMI 3 or 4): Locate the sensor on the engine block, thermostat housing, or coolant passage. Disconnect the harness, turn the ignition ON (engine OFF), and test for a 5-volt reference from the ECM, a good ground connection, and signal wire continuity.

4. 4

   If diagnosing an electrical fault (FMI 3 or 4): Check the signal wire for a short to ground (for FMI 4) or a short to another voltage source (for FMI 3).

5. 5

   If diagnosing an electrical fault (FMI 3 or 4): Measure the resistance across the disconnected sensor's terminals. Resistance should change with temperature (e.g., 9k-11k ohms cold, 600-675 ohms hot). Infinite or zero resistance indicates a failed sensor.

6. 6

   If diagnosing an overheating fault (FMI 0, 15, or 16): Use an infrared thermometer to measure the temperature at the thermostat housing to confirm if the engine is genuinely overheating.

7. 7

   If diagnosing an overheating fault (FMI 0, 15, or 16): Inspect mechanical cooling system components. Check if the thermostat is opening correctly by feeling the radiator hose or testing it in hot water. Check for a loose fan belt or signs of water pump failure (leaks, damaged impeller). Ensure the cooling fan (and fan clutch, if equipped) is operating correctly.

1. 1

   Address overheating issues (FMI 0, 15, 16)

   If a true overheating condition is found, repair the root cause first (e.g., replace a stuck thermostat, clean the radiator, repair a failing water pump).

2. 2

   Repair wiring and connectors

   If diagnostic checks reveal damaged wiring or corroded connectors, repair or replace the affected section of the harness. Ensure connectors are clean, free of moisture, and securely locked.

3. 3

   Replace the Engine Coolant Temperature Sensor

   If the sensor is confirmed faulty through resistance testing, ensure the engine is cool and relieve cooling system pressure. Have the new sensor ready to minimize coolant loss when swapping. Unscrew the old sensor, quickly install the new one, and tighten it to the manufacturer's specification. Do not overtighten. Reconnect the electrical connector.

4. 4

   Clear fault codes

   After the repair, use a diagnostic tool to clear the fault code from the ECM's memory.

5. 5

   Verify the repair

   Start the engine, let it warm up, and monitor the coolant temperature reading on the dashboard or with a scan tool to ensure it is providing a plausible and stable reading.