Case IH 17650 (F-5394-05) - ECU – Engine Control Unit (ECU / ECM): DEF/AdBlue dosing valve ECM high side or low side drivers are shorted to ground

The engine control module has detected an abnormal current draw or a direct path to ground on the electrical circuit that commands the urea/DEF injector to open and close.

• VESTRUM CVX
• Austoft 9900 sugarcane harvesters
• Farmall series (40-45-50, 115U)
• Optum tractors
• Maxxum tractors
• Magnum tractors
• Steiger tractors

1. 1

   Save the error log, erase the code, and restart the ECU to see if the fault returns, ruling out a transient voltage spike

2. 2

   Inspect the DEF dosing valve wiring, connectors, and contact surfaces for oxidation, moisture intrusion, or chafing

3. 3

   Check the ECM 12/24 volt actuator supply lines for shorts to ground or battery voltage (On Bosch MD1CE101 systems, check Supply 5 pins 5.07, 6.41 and Supply 6 pins 5.13, 6.42)

4. 4

   Use a diagnostic scan tool to perform an AdBlue/DEF dosing valve control test (UDVC) to manually command the valve and monitor the electrical draw

5. 5

   Disconnect the DEF dosing valve and check the module itself for an internal short circuit

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical damage while testing the ECU and SCR wiring.

2. 2

   Isolate the Circuit

   Disconnect the wiring harness at the DEF dosing valve and at the Engine ECU.

3. 3

   Test the Harness

   Use a digital multimeter to test the continuity of the high side and low side driver wires to ground.

4. 4

   Repair Wiring (If Applicable)

   If a short to ground is found in the harness, trace the harness to locate the chafed, melted, or pinched section. Repair the wiring or replace the SCR/DEF wiring harness section.

5. 5

   Replace the Valve (If Applicable)

   If the wiring tests good (no short to ground in the harness), the DEF dosing valve itself has failed internally. Remove the DEF lines and mounting hardware, and install a new DEF dosing valve.

6. 6

   Reassemble and Restore Power

   Reconnect all electrical connectors and restore battery power.

7. 7

   Reset Inducement

   Because this is an emissions-related fault, it will likely cause an engine derate (inducement). After the physical repair, you must use a diagnostic tool to clear the fault codes and perform an Inducement Unlock / Counter Reset.