Case IH 19153 – Engine Control Unit (ECU): DEF/AdBlue dosing valve actuator short circuit to battery in high side

The engine control system has detected unexpected voltage on the circuit that controls the injection of diesel exhaust fluid into the SCR system, preventing the dosing valve from operating correctly. This fault will trigger an emissions inducement, leading to an engine power derate or idle-lock.

• Tier 4b
• Case IH 240 Series Axial-Flow Combines
• Case IH Magnum Tractors

1. 1

   Visually inspect the harnesses and connectors going to the DEF dosing valve and supply module for damage, bent or dislocated pins, corroded terminals, or broken wires. Verify all connectors are fully seated.

2. 2

   Perform a harness flex test while monitoring the display to reveal any intermittent breaks or shorts in the wiring.

3. 3

   Turn the key to the ON position and use a multimeter to check for a short to key battery power. Measure voltage from ECU Connector-1 (high-side driver pin 84 or 23, depending on engine model) to chassis ground.

4. 4

   Evaluate voltage results: there should be no voltage present. If voltage is present, the wiring harness has a short to battery power. If no voltage is present, the short is likely internal to the dosing valve actuator or supply module.

1. 1

   Repair Wiring

   If the multimeter test revealed voltage, trace the wiring harness back from the dosing valve to the ECU. Locate the chafed or melted wire causing the short to battery power and repair the conductor.

2. 2

   Replace Component

   If the wiring tests perfectly fine, the internal circuitry of the DEF dosing valve actuator / supply module has failed. Replace the module.

3. 3

   Verify Repair

   Reconnect all harnesses and use a diagnostic scan tool (such as the Case IH Electronic Service Tool or PT-Box) to verify the status of the fault.

4. 4

   Reset Inducement

   Because this fault causes an emissions inducement (derate), you must perform an 'Inducement Unlock / Counter Reset' using the diagnostic tool once the physical repair is complete.

5. 5

   Clear Codes

   Erase the inactive fault code and return the machine to service.