Case IH 19055 – DCU (Dosing Control Unit): UREA Temperature sensor in box (electrical) _high signal _P2045 Reagent -temperature sensor of pump module -short circuit high

The temperature sensor responsible for monitoring the Diesel Exhaust Fluid (DEF / Urea / Reagent) inside the DEF pump module (supply module) is sending an abnormally high signal, indicating a short circuit high on the sensor's electrical circuit.

• Tier 4a
• Tier 4b
• Case IH Magnum 235 - 340 (Series 4)
• Case IH Steiger (350 to 600 horsepower models)
• Case IH Puma series
• Case IH Farmlift Telescopic Handlers (632, 635, 735, 742, 935)

1. 1

   Inspect the wiring harness and connectors leading to the DEF supply module for chafing, cuts, or corrosion that could cause a short circuit to a power source.

2. 2

   Connect a diagnostic scan tool to verify the active code and observe live data for the DEF pump module temperature sensor to see if it is pegged at a maximum value.

3. 3

   Turn off the ignition switch and wait until communication with the diagnostic scan tool is completely discontinued to ensure the DCU has powered down before disconnecting components.

4. 4

   Isolate the component to confirm if the short circuit is inside the module itself after ruling out harness damage.

1. 1

   Turn off the ignition switch and wait for the DEF system to purge and the DCU to fully power down.

   Communication with the scan tool will drop.

2. 2

   Locate the DEF supply module.

   Often mounted near the DEF tank or on the chassis frame.

3. 3

   Access the pump module.

   Depending on the machine model, you may need to remove protective shields, the PDU fuse box, or the air cleaner assembly to access the pump module.

4. 4

   Disconnect the main electrical harness connector from the DEF supply module.

5. 5

   Disconnect the DEF fluid hoses (suction, pressure, and backflow lines).

   Note: DEF fluid can be corrosive to metals and plastics; clean up any spills immediately.

6. 6

   Unbolt the mounting hardware and remove the faulty DEF supply module.

7. 7

   Install the new DEF supply module and secure the mounting hardware.

8. 8

   Reconnect the DEF fluid lines and the electrical harness connector.

9. 9

   Turn the ignition switch ON (without starting the engine) and use the diagnostic scan tool to clear the 19055 / P2045 fault code.

   Also clear any related codes like P20C9.