Massey Ferguson 1761.04 – Engine Control Unit (ECU) / Engine Electronic Module (EEM4): DEF Tank Level Sender Low Voltage
Issue description
The voltage signal returning from the Diesel Exhaust Fluid (DEF) tank level sensor is below the minimum expected threshold. This condition typically points to a short to ground in the sensor circuit, a defective sensor, or a stuck float.
Applies to these machines
43 machines- 4710
- 7724S
- 5712SL
- Interim Tier 4 (2012-2015)
- 7722
- 7722S
- 7615
- 5613
- 5713SL
- 7720S
- 7716
- 7718
- T4
- 7715
- 5710SL
- 7726
- 7616
- 7618
- 5608
- 4708
- 7619
- 7626
- 7726S
- 7624
- 4707
- 4709
- 5711SL
- 7614
- 7718S
- 5610
- 7620
- 7719
- 7714
- 7716S
- T4 (2015-2021)
- 5612
- 7622
- 7720
- Tier 4 (2015-2021)
- 5611
- 7715S
- 5609
- 7724
Check the cause
Visually inspect the wiring harness leading to the DEF tank fluid level sensor for signs of chafing, wear, or damage that could cause a short to ground.
Use a multimeter to verify the voltage at the sensor connector. A reading below the normal operating range confirms a short to ground or an open circuit.
Pin out the DEF level sensor circuit from the ECU to the sensor to test for continuity and shorts to the vehicle's chassis ground.
Check if the DEF tank fluid level sensor float is physically stuck inside the tank.
Repair steps
Repair Wiring
If the diagnostic tests reveal a short to ground in the harness or a damaged connector, repair or replace the affected wiring segment.
Replace the Sensor
If the wiring tests good but the voltage remains low, the internal circuitry of the DEF level sensor is defective. You will need to replace the DEF Tank Level Sensor (often integrated into the DEF Header unit).
Clear the Error Log
Once the repair is complete, save the error log and then erase it from the ECU using a diagnostic service tool.
Restart and Calibrate
Restart the ECU. Perform a DEF Level Calibration procedure and run the machine to ensure the sensor is functioning correctly and providing accurate readings without triggering an active fault.
Parts you might need
(1)DEF Tank Level Sensor / DEF Header Unit
Specific Massey Ferguson part numbers vary heavily by exact tractor model and tank size. Look up the exact DEF Header or DEF Tank Level Sensor in the AGCO parts catalog using the tractor's specific serial number.
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