Case IH 17649 (F-5394-03) - ECU – ECU / DCU: High or low side actuators of the DEF/AdBlue dosing valve ECU shorted to the battery

The control module has detected that the electrical circuit controlling the Diesel Exhaust Fluid (DEF) dosing valve has a short circuit to battery voltage (B+). This prevents the ECU from controlling the valve, leading to an inability to dose DEF and reduce NOx emissions.

• VESTRUM CVX
• Magnum series (180-380)
• Maxxum series (115-150)
• Puma series (140-240)
• Optum series
• Farmall series (80N-120C)
• Axial-Flow series (7130, 7230, 8230, 9230)
• Austoft 9900

1. 1

   Visually inspect the wiring harness between the ECU/DCU and the DEF dosing valve for chafed wires, melted insulation from exhaust heat, or pinched lines.

2. 2

   Disconnect the DEF dosing valve and inspect the connector pins for corrosion, moisture, or DEF crystal intrusion that could bridge pins and cause a short.

3. 3

   Using a multimeter, test the doser injector valve coil resistance. A healthy Bosch-style valve reads between 11 to 18 ohms. Extremely low resistance indicates the valve is internally shorted.

4. 4

   With the valve disconnected, turn the key ON and test the harness-side pins for voltage. If battery voltage is present on the ground/control wire, the wiring harness is shorted to power and must be repaired.

5. 5

   Note: Minor DEF crystal accumulation at or near the tip of the dosing valve is normal and does not indicate a failed valve.

1. 1

   Disconnect battery

   Turn off the machine and disconnect the battery to prevent further electrical damage or accidental dosing.

2. 2

   Locate DEF dosing valve

   Locate the DEF dosing valve mounted on the SCR exhaust pipe.

3. 3

   Disconnect electrical connector

   Carefully disconnect the electrical connector.

4. 4

   Disconnect DEF supply line

   Disconnect the DEF supply line. Caution: Have a rag ready, as DEF is highly corrosive to metal and wiring. Clean up any spills immediately with warm water.

5. 5

   Remove mounting hardware

   Remove the mounting bolts/clamp securing the dosing valve to the exhaust pipe.

6. 6

   Clean mounting port

   Clean the mounting port on the exhaust pipe, ensuring no old gasket material or excessive carbon/DEF buildup remains.

7. 7

   Install new DEF dosing valve

   Install the new DEF dosing valve with a new gasket/seal. Torque the mounting hardware to OEM specifications.

8. 8

   Reconnect lines and connector

   Reconnect the DEF supply line and the electrical connector.

9. 9

   Reconnect battery and test

   Reconnect the battery. Use a diagnostic scan tool to clear the fault codes and run a DEF system prime/dosing test to verify operation and check for leaks. (Note: Some replacement modules may require programming/calibration to the ECU upon installation.)