Massey Ferguson 3532.04 – Engine Control Unit (ECU): DEF Tank Level Sensor Issue (ECU)

The Engine Control Unit (ECU) has received a signal from the DEF tank level sensor that is outside of its expected range or performance parameters. This indicates a potential fault within the sensor itself, its electrical circuit, or related components of the Selective Catalytic Reduction (SCR) system. If left unaddressed, this irregular signal can lead to the activation of warning lights and cause the engine to derate, limiting power output to protect the emissions system.

• 4710
• 7724S
• 5712SL
• 7722S
• 7722
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 4708
• 7726S
• 4707
• 4709
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Visually inspect the DEF tank, cap, and breather to ensure no dust or moisture has contaminated the fluid.

2. 2

   Ensure the DEF fluid is fresh and at the correct concentration (32.5% urea). Check the sensor probe for heavy DEF crystallization or freezing.

3. 3

   Inspect the wiring harness leading to the DEF tank level sensor for any chafing, open circuits, or shorts to a low voltage source.

4. 4

   Connect a diagnostic tool, save the error log, and then erase it. Restart the ECU to see if the fault returns immediately, indicating a hard electrical failure.

1. 1

   Preparation

   Clean the area around the DEF tank neck thoroughly. The system is highly sensitive to contamination; treat the tank neck like a jet fuel filler.

2. 2

   Access the Tank

   On many models (like the 5700 SL series), you must remove the tractor step to access and remove the DEF tank.

3. 3

   Drain the Tank

   To make handling easier, drain the DEF tank (which holds approximately 40 liters). Note: The drain plug tightening torque upon reinstallation is 6.5 Nm ± 0.5 Nm, and it must be fitted with a new seal.

4. 4

   Disconnect Lines

   Carefully disconnect the electrical connectors and the heated supply/return lines from the pump/sensor module. Be careful not to nick the O-rings, as this will cause air ingress and priming faults later.

5. 5

   Replace Sensor

   Remove the faulty DEF tank level sensor/header unit and install the new genuine AGCO replacement part.

6. 6

   Reassembly

   Reinstall the tank, reconnect all heated lines and electrical connections securely, and reinstall the steps/access panels.

7. 7

   Refill and Clear Codes

   Refill the tank with fresh DEF. Use a diagnostic tool to clear the 003532.04 fault code and run a system test to verify the ECU is reading the tank level correctly.