Case IH F-1761-17 - ECU – Engine Control Unit (ECU): DEF/AdBlue level too low warning is active - Stage 1

The Diesel Exhaust Fluid (DEF) level in the tank has dropped below the minimum acceptable threshold. As a Stage 1 warning, it serves as an initial alert to the operator to refill the tank before the system escalates to a Stage 2 warning, which will actively derate engine power and limit machine operation.

• MAGNUM AFS Connect
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Puma 150
• Puma 165
• Puma 185
• Puma 200
• Puma 220
• Puma 240
• Quadtrac 470
• Quadtrac 500
• Quadtrac 540
• Quadtrac 580
• Quadtrac 620
• Farmall 35C
• Farmall 90C
• Farmall 110U
• Axial-Flow 240 Series
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Patriot 3230
• Patriot 3330
• Patriot 4430

1. 1

   Visually inspect the DEF/AdBlue tank to confirm if it is actually empty or low

2. 2

   If the tank is full, inspect the DEF tank level sensor and its wiring harness for chafed wires, corrosion in the connector, or physical damage to the sensor header

3. 3

   Use a diagnostic tool to check for related sensor circuit codes (e.g., 19650 or 19651) which indicate an electrical failure of the sensor

1. 1

   Refill the Tank

   Park the machine on a level surface. Clean the area around the DEF filler neck to prevent dirt from entering the SCR system, and fill the tank with fresh, high-quality Diesel Exhaust Fluid (ISO 22241 standard).

2. 2

   System Reset

   Turn the ignition key to the ON position without starting the engine. Allow the ECU a moment to register the new fluid level. Start the engine; the Stage 1 warning should clear automatically once the sensor detects the fluid.

3. 3

   Sensor Replacement

   If the code persists with a full tank, disconnect the machine's battery. Depending on the machine model, partially drain the DEF tank to prevent spills. Disconnect the electrical harness and the fluid lines from the top of the DEF level sensor unit. Unscrew the retaining ring or mounting bolts securing the sensor to the tank. Carefully extract the old sensor assembly. Install the new DEF level sensor, ensuring the O-ring/seal is properly seated to prevent leaks. Reconnect the fluid lines and electrical harness.

4. 4

   Final Clearance

   Reconnect the battery, turn on the machine, and use an Electronic Service Tool (EST) to clear any stored inactive fault codes.