Massey Ferguson E1761.18 – Engine Control Unit (ECU): DEF Tank Level Low

The Engine Control Unit (ECU) has detected a low level of Diesel Exhaust Fluid (DEF) in the tank. The Selective Catalytic Reduction (SCR) system requires a sufficient level of DEF to inject into the exhaust stream to reduce harmful emissions and maintain compliance. When the fluid drops below a critical threshold, the sensor alerts the ECU, triggering this fault code and a dashboard warning. Ignoring a low DEF warning can lead to the engine entering a reduced power mode or being prevented from starting.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 4707
• 4708
• 4709
• 4710
• 5710 S
• 5711 S
• 5712 S
• 5713 S
• 6713 S
• 6714 S
• 6715 S
• 6716 S
• 6718 S
• 7714
• 7716
• 8650
• 8660
• 8690
• 8737 S
• IDEAL 7
• IDEAL 8
• IDEAL 9

1. 1

   Visually inspect the actual fluid level in the DEF/AdBlue tank (do not rely solely on the dash gauge)

2. 2

   Ensure the DEF is not contaminated with diesel, water, or dirt, which can foul the sensor and trigger erratic readings

3. 3

   Inspect the wiring harness leading to the DEF tank level sensor (often integrated into the DEF header unit) for chafing, open circuits, or shorts to a high source

4. 4

   Check the DEF tank, pump module, and heated lines for leaks, crystallization, or damaged O-rings that could cause the fluid to drain prematurely

1. 1

   Refill the Tank

   Fill the DEF tank with a valid, high-quality reducing agent (DEF/AdBlue).

2. 2

   Clear the Code

   Connect your diagnostic service tool (e.g., WinEEM3s/WinEEM4s or equivalent AGCO diagnostic tool). Save the error log, and then erase the active fault codes.

3. 3

   Restart the ECU

   Turn the tractor off, wait for the ECU to power down completely, and restart the engine to allow the ECU to poll the sensor.

4. 4

   Sensor Replacement

   If the tank is full but the code remains active (or toggles to FMI 3/FMI 4), the DEF tank level sensor/header assembly has failed internally and must be replaced.

5. 5

   Recalibration

   If the DEF header or dosing unit is replaced, use the diagnostic tool to calibrate the new emissions components.