Case IH 19086 – Engine Control Unit (ECU) / Dosing Control Unit (DCU) / Urea Control Module (UCM): DEF/AdBlue pressure line heater failure and DEF/AdBlue tank temperature is too low.

The engine's emissions system has detected a malfunction in the heating circuit for the Diesel Exhaust Fluid (DEF) pressure line (such as an open circuit, short to ground, or short to battery). Simultaneously, the system is registering that the DEF tank temperature has dropped below acceptable operating limits.

• Tier 4b
• 240 Series Axial-Flow Combines
• Magnum Series (180, 190, 210, 225, 235-340)
• Farmall Series
• Steiger Series
• Case N-Series Tractor Loader Backhoes (TLBs)
• Dozers (850M, 1150M)

1. 1

   Turn the machine completely off and back on to rule out temporary logic errors in the ECU

2. 2

   Inspect the Coolant Control Valve (CCV) to ensure it is not stuck closed or leaking. Verify coolant lines to the DEF level unit are warm when the engine is at operating temperature

3. 3

   Verify DEF tank hose routing. Ensure the DEF heater line with the red band is connected to the top tube running to the front part of the engine head

4. 4

   Inspect the wiring harness and connectors for the Urea Pressure Line Heater for corrosion, open circuits, or shorts

5. 5

   Measure the resistance of the DEF heater circuit on the DEF line side (should be 5.5 ohms ± 1 ohm at 68°F/20°C). Infinite or out-of-spec resistance indicates a failed line heater

1. 1

   Turn off the equipment and allow the engine and coolant system to cool completely.

   WARNING: Never remove coolant lines or DEF lines while the engine is hot and the system is pressurized.

2. 2

   Locate the DEF supply and pressure lines running from the DEF tank to the dosing module on the exhaust.

3. 3

   Disconnect the electrical harness connectors for the DEF pressure line heater.

4. 4

   Remove the retainer clips holding the DEF line assembly to the frame brackets and disconnect the DEF pressure line fittings.

   Note: Catch any spilled DEF and clean the area immediately with warm water, as DEF is highly corrosive to metal.

5. 5

   Route the new DEF pressure line heater hose assembly, reattach all frame clips to prevent chafing, and reconnect the electrical harness.

6. 6

   Replace the Coolant Control Valve (CCV) / heater valve if diagnostics found it was sticking and causing the tank temperature too low symptom.

7. 7

   Turn the key on and use the Case IH Electronic Service Tool (EST) or the in-cab diagnostic display to clear fault code 19086.

   Run the machine to operating temperature to verify the code does not return.