Case IH 19748 (DTC 833A) - ECU – DCU (Dosing Control Unit) / ACM (Aftertreatment Control Module) / Engine ECU: Too high UREA Temperature in Pump module or Leakage test failed (Emergency shut off)

The system has detected an over-temperature condition in the DEF/AdBlue supply module pump motor. When the DEF fluid or the pump itself gets too hot, the system triggers an emergency shut-off to prevent damage, which will eventually lead to an engine power derate.

• MAXXUM T4E
• Steiger 350
• Steiger 370
• Steiger 400
• Steiger 420
• Steiger 450
• Steiger 470
• Steiger 500
• Steiger 540
• Steiger 550
• Steiger 580
• Steiger 600
• Steiger 620
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 235
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Puma
• Maxxum
• Optum
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Axial-Flow 150 Series
• Axial-Flow 160 Series
• Axial-Flow 250 Series
• Axial-Flow 260 Series
• Patriot Sprayers
• Trident Sprayers
• Titan Floaters

1. 1

   Check the Coolant Control Valve (CCV) / DEF Heater Valve: Feel the coolant lines going to the DEF tank; if they are hot after the tractor has been running in warm weather, the valve is stuck open.

2. 2

   Check for Crossed Coolant Lines: Ensure the DEF tank heater hoses were not installed incorrectly (e.g., the line with the 'red' band is on the wrong tube).

3. 3

   Sensor Plausibility Check: Let the engine cool completely to ambient temperature. Use an electronic service tool to read the DEF pump temperature sensor, upstream exhaust sensor, and downstream exhaust sensor to ensure they all read the same ambient temperature.

4. 4

   Inspect for Crystallization: Check the DEF injector and the pump's main filter for urea crystallization blockages, which can overwork the pump motor and cause it to overheat.

1. 1

   Reboot the System

   Turn the tractor off completely and let it sit to allow the ACM to perform its delayed reverting/draining strategy (pumping DEF back into the tank).

2. 2

   Test and Replace the Heater Valve (If Applicable)

   If the diagnostic checks reveal the Coolant Control Valve is stuck open, drain the localized coolant, remove the defective CCV, and install a new heater control valve. Clear the codes and test run the machine.

3. 3

   Clean the DEF System

   If crystallization is found, flush the DEF lines with distilled water and replace the DEF pump main filter.

4. 4

   Replace the DEF Supply Module (Pump)

   If the coolant valve is functioning properly, the lines are routed correctly, and the internal temperature sensor (P2043) is confirmed out of range, the DEF pump itself has suffered internal electrical/sensor failure. Disconnect the battery, electrical harness, coolant lines, and DEF fluid connectors. Unbolt the pump, install the new DEF supply module, and reconnect all lines and harnesses.

5. 5

   Clear Codes and Prime

   Use a diagnostic scan tool to clear the 19748 / 833A fault codes. Cycle the key to allow the new pump to prime the system and verify that the pump emits a steady humming sound without erratic noises.