Case IH 17777 (F-5862-15) - ECU – Engine Control Unit (ECU): DEF/AdBlue supply module pump motor - Temperature above maximum limit

The electric motor inside the Diesel Exhaust Fluid (DEF) supply pump is overheating. This condition is typically caused by the pump overworking due to a crystallization blockage in the DEF lines or filter, a lack of cooling, or a failure of the temperature sensor internal to the pump module. If ignored, this fault will eventually force the engine into a power derate mode to protect the emissions system.

• VESTRUM CVX
• Magnum (180-370)
• Steiger (350-600)
• Maxxum (110-140)
• Puma (130-215)
• Axial-Flow series (5130-9230, 240/250 series)
• Austoft 9900
• Patriot series (4430)
• Farmlift telehandlers

1. 1

   Inspect for blockages (overworking pump cause): Check and clean the DEF filter and dosing valve, as crystallization blockages force the pump to work harder and raise its temperature.

2. 2

   Check wiring and connectors (false reading cause): Inspect the wiring harness and connectors at the DEF supply module for corrosion, chafing, or short circuits that can cause false temperature readings to be sent to the ECU.

3. 3

   Inspect coolant lines (lack of cooling cause): Ensure the engine coolant lines regulating the DEF supply module are not pinched, leaking, or blocked, which would prevent the pump from cooling down.

4. 4

   Live data testing (internal sensor failure cause): Use a dealer-level diagnostic scan tool to monitor live temperature data of the DEF pump motor. If it reads impossibly high when cold, the internal sensor has failed and the module must be replaced.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and allow the exhaust and DEF systems to completely cool. Clean the area around the DEF supply module to prevent dirt from entering the sensitive SCR system.

2. 2

   Disconnect Lines

   Carefully disconnect the DEF/AdBlue feed lines and the coolant lines from the supply module. Note: Clean up any DEF spills immediately with warm water, as it is highly corrosive to metal and degrades plastics.

3. 3

   Disconnect Electrical

   Unplug the electrical wiring harness connector from the module.

4. 4

   Removal

   Remove the mounting hardware (bolts/brackets) securing the DEF supply module to the chassis or tank flange, and carefully pull the unit out.

5. 5

   Installation

   Mount the new DEF supply module and secure the hardware. Reconnect the coolant lines, DEF feed lines, and electrical harness.

6. 6

   Programming/Calibration

   A new DEF supply module must be programmed and calibrated to the vehicle's ECU using a diagnostic tool before the engine will clear the derate condition and operate normally.