Massey Ferguson U 1761 – SCR Management Module / Engine ECU: Level sensor in urea tank

Indicates an error with the Level sensor in urea tank (DEF or AdBlue tank level sensor). The exact underlying condition is determined by the FMI sub-code.

• 8600 Series
• MF 8650
• MF 8690
• 6700 S Series
• 4700 Series
• 5700 Series
• 7600 Series
• 7700 Series
• 8700 Series

1. 1

   Verify DEF/AdBlue fluid level physically to rule out a genuinely empty tank.

2. 2

   Inspect the DEF tank cap and breather for dirt, diesel, or water contamination.

3. 3

   Inspect the urea fluid sensor wiring harness and connector for rust, corrosion, loose connections, open circuits, or shorts to ground.

4. 4

   Connect the AGCO Electronic Diagnostic Tool (EDT) to observe live DTC information and verify sensor voltage.

1. 1

   Purge Cycle

   Turn off the engine and wait for the DEF system to complete its automatic purge cycle (the pump reverses briefly at shutdown to purge fluid back to the tank, preventing crystallization in the lines).

2. 2

   Disconnect Power

   Disconnect the tractor's battery to ensure safety while working on the SCR electrical system.

3. 3

   Drain the Tank

   If the DEF fluid is contaminated or if the sensor is mounted low on the tank assembly, drain the DEF/AdBlue tank into a clean container.

4. 4

   Disconnect Harness

   Unplug the electrical wiring harness from the DEF tank level sensor/header unit.

5. 5

   Remove Sensor

   Unbolt or unscrew the locking ring securing the DEF tank level sensor module to the tank and carefully extract the unit.

6. 6

   Install New Part

   Insert the new OEM DEF level sensor, ensuring the O-ring/seal is perfectly seated to prevent dust or moisture ingress. Secure the mounting bolts/ring.

7. 7

   Reassembly

   Reconnect the wiring harness and the battery.

8. 8

   Refill

   Refill the tank with fresh, uncontaminated DEF/AdBlue (32.5% urea solution).

9. 9

   Clear Codes

   Use the AGCO EDT diagnostic scanner to clear the U 1761 fault code and run an engine cycle to verify the sensor is reading the correct level.