Case IH 19759 – Engine ECU (VCM / DCU): Warning for level of reducing agent stage 4

The DEF (Diesel Exhaust Fluid) tank is critically low or empty, triggering a Stage 4 warning and forcing the machine into a severe torque reduction or idle-only limp mode (inducement strategy).

• Tier 4b
• Magnum
• Steiger
• Puma
• Optum
• 7230
• 8230
• N-Series Tractor Loader Backhoes

1. 1

   Physically check the fluid level in the DEF tank.

2. 2

   Inspect the DEF tank, lines, and dosing pump for physical leaks that may have caused the fluid level to drop unexpectedly.

3. 3

   Inspect the wiring harness and connector going to the DEF level sensor for corrosion, chafing, or rodent damage.

4. 4

   Look for other active fault codes related to DEF quality, DEF temperature, or DEF pressure to determine if the sensor itself has failed.

1. 1

   Refill the DEF Tank

   Fill the tank with fresh, high-quality Diesel Exhaust Fluid. Do not overfill, but ensure it is topped off enough to clear the low-level threshold.

2. 2

   Reset the Inducement Counter

   Turn the ignition key to the ON position and wait for the system to register the new DEF level.

3. 3

   Run the Engine

   Once the fluid is registered, start the engine. The system may require the engine to run for up to 30 minutes to confirm the system is functioning normally and to fully unlock the inducement counter.

4. 4

   Clear the Code

   If the engine returns to full power, the code will move from 'Active' to 'Stored/Pending' and can be cleared using a diagnostic tool (like the CNH EST, TEXA, or Cojali Off-Highway kits).

5. 5

   Sensor Replacement (If Refilling Fails)

   If the tank is full but the Stage 4 warning persists, the DEF level sensor/header unit is faulty. Drain the DEF tank, disconnect the electrical and fluid lines from the header unit, unbolt the header from the tank, and install a new DEF sending unit.