Case IH 19379 – DCU (Dosing Control Unit): UREA Temperature too low during commissioning | Temperatures not plausible during commissioning

During the system startup (commissioning) phase, the temperature sensor located within the DEF (Diesel Exhaust Fluid) supply module is reporting a temperature that is implausibly low. This indicates a failure of the temperature sensor itself, a wiring issue to the module, or a failure in the DEF heating system causing the fluid to be frozen or improperly heated.

• Tier 4b
• Steiger Series 350, 400, 450, 500, 550, 600 (NA and QT NA)
• Rowtrac Series 350, 400, 450, 500
• Magnum Series 180, 190, 210, 225, 235, 260, 290, 340, 370 (Series 4)
• Maxxum Series 110, 115, 120, 125, 130, 140
• Puma Series 130, 145, 160, 170, 185, 200, 215
• Farmall Series 95A, 100C, 110C, 115U
• Patriot/Titan sprayers
• Farmlift telehandlers

1. 1

   Verify the DEF/AdBlue concentration (should measure 32.5% high-grade urea and 67.5% distilled water). Drain and replace if incorrect.

2. 2

   Check the DEF supply module and lines for actual freezing if operating in cold climates. Ensure the DEF tank heater and line heaters are functioning properly.

3. 3

   Inspect the electrical harness and connectors at the DEF supply module for corrosion, bent pins, or open/short circuits that could cause an implausible sensor reading.

4. 4

   Inspect the dosing injector tip and mixing chamber for white scale build-up (deposits) which can prevent proper DEF vaporization.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and allow the SCR system to complete its purge cycle before servicing.

2. 2

   Removal

   Relieve any residual pressure in the DEF lines. Disconnect the electrical harness and the DEF plumbing lines from the supply module.

3. 3

   Dismounting

   Unbolt and remove the faulty DEF supply module from its mounting bracket (tank-mounted or remote-mounted depending on the tractor architecture).

4. 4

   Installation

   Mount the new DEF supply module. Reconnect the plumbing lines and electrical connectors securely.

5. 5

   Refill

   Refill the system with fresh, correctly concentrated DEF.

6. 6

   Clearing the Code / Relearning

   Bring the engine to operating temperature and run under load until the SCR system determines it is operating properly. If the code is still active after running the engine for 30 minutes under load, further diagnostics using the Electronic Service Tool (EST) are necessary.