Deutz-Fahr M37 – Engine ECU (EMR): Low coolant level

The coolant level sensor located in the coolant expansion tank has detected that the engine's antifreeze/coolant mixture has dropped below the minimum safe operating threshold. If ignored, this condition can lead to severe engine overheating and catastrophic engine damage.

• Tractors equipped with FARMotion KD/KE engines
• 5D VSF CVT (Tier 4i) and 5000 Series tractors
• 6 Series tractors (e.g., 6120, 6130, 6140)
• Machines utilizing Deutz TCD 3.6 and TCD 4.1 engines
• Various Deutz-Fahr combine harvesters (e.g., 6040, 6095 HTS, C6205 TS)

1. 1

   Visual Coolant Check: Safely check the actual physical coolant level in the expansion tank (ensure the engine is completely cool before opening).

2. 2

   Leak Inspection: If the coolant is genuinely low, inspect the radiator, water pump, and all upper/lower coolant hoses for physical leaks.

3. 3

   Wiring & Connector Check: If the coolant tank is full but the M37 code is active, inspect the wiring harness and the connector at the coolant level sensor. Look for corrosion, backed-out pins, or a short circuit.

4. 4

   Sensor Verification: Test the sensor for continuity. If the tank is full and the wiring harness is receiving the correct reference voltage from the EMR, the sensor itself has failed internally.

1. 1

   Safety First

   Turn off the machine, remove the key, and allow the engine to cool completely to depressurize the cooling system.

2. 2

   Top Off Fluids (If Applicable)

   If the tank is low, top it off with the OEM-specified coolant. Clear the code via the dash or SERDIA diagnostic tool and run the machine to see if the code returns.

3. 3

   Disconnect the Sensor

   If the sensor is deemed faulty, locate the coolant level sensor on the expansion tank and disconnect its electrical pigtail/connector.

4. 4

   Remove the Sensor

   Depending on the tank design, the sensor may be threaded or held in by a retaining clip. Carefully extract the sensor. (Note: Have a catch pan ready, as a small amount of coolant may leak out during removal).

5. 5

   Install the New Sensor

   Insert the new coolant level sensor, ensuring the O-ring or seal is properly seated to prevent leaks.

6. 6

   Reassembly

   Reconnect the electrical harness.

7. 7

   Clear Codes

   Turn the key to the ON position. Use the tractor's instrument panel or the Deutz SERDIA diagnostic software to clear the EMR fault memory. Start the engine and verify the warning light is extinguished.