Case IH 17486 (F-522006-31) - ECU – ECU: DEF/AdBlue reverting pump - ECU driver circuit over temperature failure

The reverting pump is a function of the DEF supply module responsible for purging (reverting) DEF fluid out of the dosing lines and back into the tank when the engine shuts down to prevent freezing and crystallization. This code indicates that the internal driver circuit within the control module that powers this pump has exceeded its maximum safe operating temperature.

• VESTRUM CVX
• Magnum
• Steiger
• Puma
• Maxxum
• Optum
• Farmall
• Axial-Flow series
• Patriot series

1. 1

   Check the Coolant Control Valve (CCV) to ensure it is not stuck open or leaking, which would continuously flow hot engine coolant through the DEF storage tank and overheat the fluid and pump module.

2. 2

   Inspect DEF lines and the pump suction tube for crystallization or blockages that force the pump to overwork and overheat the driver circuit.

3. 3

   Test DEF fluid quality to ensure it is at the correct concentration (32.5% urea) and is not degraded, cloudy, or contaminated with diesel fuel.

4. 4

   Inspect the wiring harness leading to the DEF pump for chafing, shorts to ground, or shorts to battery voltage causing electrical overloads.

1. 1

   Drain the DEF Tank

   If the fluid is contaminated or degraded, drain the tank completely.

2. 2

   Flush the Lines

   Flush the DEF dosing lines with warm water to dissolve and clear any crystallized urea.

3. 3

   Remove the DEF Pump Module

   Disconnect the electrical connectors, DEF lines, and coolant heating lines, then unbolt and remove the unit.

4. 4

   Install the New Module

   Install the replacement DEF pump/dosing module and reconnect all lines and harnesses. Replace the DEF pre-filter (e.g., Case IH #84247272) during this service.

5. 5

   Program the Module

   The new Bosch DEF module must be programmed to the vehicle's ECU using a diagnostic scan tool after installation.

6. 6

   Test the System

   Clear the fault codes and run a dynamic DEF leakage/dosing test via the scan tool to verify the system primes and reverts correctly without throwing over-temperature codes.