Case IH 19154 – DCU (Dosing Control Unit): DEF/AdBlue supply module pump temperature is too low to activate pump

The control module is preventing the DEF pump from activating because it is reading a temperature that is too low (often due to frozen DEF fluid or a failed internal temperature sensor), or it is detecting an open circuit (unplugged motor/broken wire) that is preventing the pump motor from running.

• Tier 4b
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Steiger Rowtrac
• Steiger Quadtrac
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Puma 140
• Puma 150
• Puma 165
• Puma 185
• Puma 200
• Puma 220
• Puma 240
• Maxxum 115
• Maxxum 125
• Maxxum 135
• Maxxum 145
• Maxxum 150
• Optum 270
• Optum 300
• Farmall 120A
• Farmall 130A
• Farmall 140A
• Axial-Flow 240 series
• Axial-Flow 5140
• Axial-Flow 5150
• Axial-Flow 6150
• Axial-Flow 7150
• Axial-Flow 8240
• Axial-Flow 9240
• Patriot 2250
• Patriot 3240
• Patriot 3340

1. 1

   Verify Active Status: Check if the fault is currently active or stored. If inactive, the issue may have been temporary (e.g., operating in extreme cold before the tank heater could thaw the fluid).

2. 2

   Check for Freezing: Verify that the DEF tank heater and supply line heaters are functioning properly. The pump will not activate if the system is frozen.

3. 3

   Inspect Wiring and Connectors: Physically inspect the wiring harness and electrical connectors at the DEF supply module. Look for unplugged connectors, backed-out pins, or corroded terminals.

4. 4

   Load-Test Power and Ground: Check the power and ground circuits to the DCU and the DEF pump using a multimeter. Place the circuits under a load to ensure the wiring can carry the necessary current.

5. 5

   Check for Related Codes: Look for accompanying codes such as 19155 (Pump Motor Blocked) or 19156 (Pump Overspeed) which point directly to a mechanical failure inside the pump.

1. 1

   Thaw the System (If Applicable)

   If the machine is in freezing conditions, allow the machine's DEF heating system adequate time to thaw the fluid. If the code clears after thawing, no parts replacement is necessary.

2. 2

   Repair Wiring

   If physical damage or an unplugged connector is found at the DEF pump, repair the wiring harness or securely seat the connector.

3. 3

   Replace the DEF Pump

   If the wiring, power, and ground are verified good, the heaters are functioning, and the pump still reports an open circuit or invalid temperature preventing activation, the DEF Supply Module has failed internally and must be replaced.

4. 4

   Disconnect Fluid Lines

   Drain the DEF tank (or clamp the supply lines) and disconnect the suction, return, and dosing lines from the pump module.

5. 5

   Remove the Module

   Disconnect the electrical harness from the pump. Unbolt the DEF pump from its mounting bracket.

6. 6

   Install the New Module

   Mount the new DEF pump, reconnect the fluid lines, and plug in the electrical harness. Ensure the DEF fluid is clean and uncontaminated, as dirty fluid will destroy the new pump.

7. 7

   Clear Codes and Test

   Use an Electronic Service Tool (EST) to clear the fault codes. Run the machine at operating temperature or initiate an SCR system test/regeneration cycle to verify the pump is delivering reagent and the code does not return.