Massey Ferguson 109.03 – ECU: Coolant Pressure Sensor Signal Voltage High (ECU)

The Engine Electronic Management (EEM) system has detected that the measured voltage signal from the coolant pressure sensor is above the normal operating range, or there is an open circuit in the sensor wiring.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S

1. 1

   Check the error log using a diagnostic tool (e.g., WinEEM3s/WinEEM4) to verify if the CAN message indicates an active fault.

2. 2

   Inspect the coolant pressure sensor wiring harness for defects, specifically looking for an open circuit or a wire shorted to a high voltage source.

3. 3

   Temporarily connect a known-good coolant pressure sensor to the harness to see if the voltage returns to the normal range. If the code clears or changes status, the original sensor is defective.

1. 1

   Preparation

   Turn off the tractor, remove the key, and allow the engine and cooling system to cool down completely to avoid burns and relieve system pressure.

2. 2

   Locate the Sensor

   Locate the coolant pressure sensor on the engine cooling circuit (on some AGCO Power engines, it is located near the expansion tank or thermostat housing).

3. 3

   Disconnect Wiring

   Carefully unplug the 3-pin electrical connector from the coolant pressure sensor.

4. 4

   Remove the Sensor

   Unthread the defective coolant pressure sensor from its port. Have a rag ready to catch any minor coolant spillage.

5. 5

   Install the New Sensor

   Thread the new OEM sensor into the port. If required by the workshop manual, apply the specified thread sealant (e.g., Loctite 242/270) to the threads before installation.

6. 6

   Reconnect and Clear Codes

   Reconnect the electrical harness. Turn the ignition on and use your diagnostic service tool to clear the stored 00109.03 fault code from the ECU.

7. 7

   Test

   Start the engine and verify that the warning lamp remains off and the code does not return. Check for any coolant leaks around the new sensor.