Case IH 19117 – Engine Control Unit (ECU), Dosing Control Unit (DCU), or Vehicle Control Module (VCM): DEF/AdBlue tank level is too low

This fault code indicates that the sensor inside the Diesel Exhaust Fluid (DEF) tank has detected that the fluid level has dropped below the minimum acceptable threshold. If left unaddressed, this condition will eventually lead to an SCR (Selective Catalytic Reduction) inducement, causing the engine to derate its power to comply with emissions regulations.

• Tier 4b
• Farmall (90C, 100C, 110U)
• Magnum (250-380)
• Puma (150-240)
• Steiger
• Quadtrac (470-620)
• Axial-Flow (7230, 8230, 9230)
• Patriot (3230, 3330, 4430)
• Case N-Series Loader Backhoes

1. 1

   Visually inspect the actual fluid level in the DEF/AdBlue tank to confirm if it is genuinely empty (do not rely solely on the cab gauge).

2. 2

   Inspect the DEF tank, supply lines, and the dosing module for any visible leaks, cracks, or physical damage.

3. 3

   Check the tank for DEF crystallization or contamination (such as diesel fuel accidentally mixed into the DEF tank), which can cause the sensor float mechanism to stick.

4. 4

   If the tank is full but the code remains active, inspect the wiring harness and connector at the DEF tank level sensor (DEF Head Unit) for corrosion, bent pins, moisture intrusion, or wire chafing.

1. 1

   Refill the Tank

   Fill the DEF/AdBlue tank with fresh, high-quality Diesel Exhaust Fluid that meets ISO 22241 standards.

2. 2

   Cycle the Key

   Turn the machine's ignition on and off to allow the ECU to poll the sensor and register the new fluid level. If the code goes inactive, the issue was simply a low tank.

3. 3

   Clean the Connection

   If the tank is full but the code persists, disconnect the DEF level sensor connector. Clean the contacts with an electrical contact cleaner, apply dielectric grease, and reconnect.

4. 4

   Replace the Sensor Assembly

   If the wiring is intact but the sensor fails to read the correct level (often due to internal failure or severe crystallization), the sensor has failed. Drain the DEF tank, unscrew/unbolt the DEF Head Unit from the top of the tank, and install a new sensor assembly.

5. 5

   Clear Codes

   Use an OEM diagnostic tool (such as the CNH Electronic Service Tool - EST) to clear the 19117 fault code and verify that the DEF level reads correctly on the machine's display.