Case IH 19505 (F-4337-31) - ECU – DCU (Dosing Control Unit): DEF/AdBlue supply module temperature sensor cold start plausibility failure

The system has detected that the temperature reading from the sensor located inside the DEF pump module is out of the expected or allowable range during a cold start. The system compares this reading against other ambient and engine temperature sensors; if the DEF pump temperature reading is implausible, this code is triggered.

• VESTRUM CVX
• Magnum Tractors 180, 200, 220, 235, 240, 250, 260, 290, 315, 340
• Steiger Tractors 350 through 600
• Puma Tractors 150, 165, 175, 185, 200, 210
• Maxxum Tractors 115, 125, 135, 140, 145
• Axial-Flow Combines 5130-9230 series
• Axial-Flow Combines 5140-9240 series
• Patriot Sprayers 2250, 3240, 3340, 4430
• Titan Floaters 3030, 3530, 4030, 4530

1. 1

   Inspect the wiring harness and the main electrical connector at the DEF supply module for corrosion, moisture ingress, or damaged pins

2. 2

   Check the DEF tank, pump, and lines for crystallization or freezing that could cause erratic pressure and temperature readings

3. 3

   Verify if the tractor's DCU/ECM software is up to date, as updates frequently adjust sensor plausibility parameters

4. 4

   If wiring is intact and software is current, the internal sensor has likely failed, requiring module replacement

1. 1

   Preparation

   Turn off the machine and wait at least 2 to 5 minutes before disconnecting the battery. Note: The DEF system runs a purge cycle after key-off to empty the lines. Interrupting this can damage the system.

2. 2

   Locate the Module

   Locate the DEF supply module, which is typically mounted near the DEF tank or on the frame rail.

3. 3

   Disconnect Lines

   Carefully disconnect the DEF suction, pressure, and backflow lines from the pump. Have a catch pan ready for minor fluid spillage. Clean up any spilled DEF immediately with warm water to prevent corrosive damage to surrounding metal.

4. 4

   Disconnect Electrical

   Unplug the main electrical harness connector from the module.

5. 5

   Remove the Pump

   Unbolt the DEF supply module from its mounting bracket and remove it.

6. 6

   Install the New Pump

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

7. 7

   Reconnect

   Reconnect the DEF fluid lines (ensuring they click securely into place) and plug in the electrical connector.

8. 8

   Programming/Calibration

   The new DEF module must be programmed and calibrated to the vehicle using the Case IH Electronic Service Tool (EST). The system will not function correctly, and the tractor may remain in derate, without this software initialization.

9. 9

   Testing

   Clear the stored fault codes, start the engine, and run an SCR system dosing test via the diagnostic tool to verify proper pressure and temperature readings.