Case IH 17684 (F-4365-06) - ECU – Engine Control Module (ECM / ECU): DEF/AdBlue quality sensor failure - temperature signal shorted to battery

The control module is receiving a voltage signal from the DEF/AdBlue quality sensor's temperature circuit that is equal to or near battery voltage. This indicates a short circuit to a power source. The short can occur internally within the sensor itself or externally in the machine's wiring harness where the signal wire has rubbed against a 12V/24V power wire.

• VESTRUM CVX
• Austoft 9900
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 115U
• 240 Series Combines

1. 1

   Inspect the wiring harness connecting the DEF/AdBlue quality sensor to the ECM for chafed insulation, melted wires, or pinched areas

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or DEF fluid ingress

3. 3

   With the sensor disconnected and the key ON, measure the voltage at the temperature signal pin on the harness side (battery voltage indicates a harness short)

4. 4

   If the harness tests normal with no voltage on the signal wire, the short is internal to the DEF quality sensor

1. 1

   Turn off the equipment and disconnect the battery to prevent electrical spikes during the repair.

   Turn off the equipment and disconnect the battery to prevent electrical spikes during the repair.

2. 2

   Locate the DEF/AdBlue quality sensor, which is mounted directly on the top or side of the DEF/AdBlue tank assembly.

   Locate the DEF/AdBlue quality sensor, which is mounted directly on the top or side of the DEF/AdBlue tank assembly.

3. 3

   If the diagnostic tests pointed to a harness issue, locate the shorted section of the wire, repair the damaged wires, and re-loom the harness.

   If the diagnostic tests pointed to a harness issue, locate the shorted section of the wire, repair the damaged wires, and re-loom the harness.

4. 4

   If the sensor is internally shorted (which is the most common cause), disconnect the electrical connector from the sensor.

   If the sensor is internally shorted (which is the most common cause), disconnect the electrical connector from the sensor.

5. 5

   Thoroughly clean the area around the sensor base to prevent dirt or debris from falling into the DEF tank.

   Thoroughly clean the area around the sensor base to prevent dirt or debris from falling into the DEF tank.

6. 6

   Remove the mounting hardware or retaining ring securing the sensor to the tank.

   Remove the mounting hardware or retaining ring securing the sensor to the tank.

7. 7

   Carefully extract the old sensor assembly.

   Carefully extract the old sensor assembly.

8. 8

   Install the new DEF quality sensor, ensuring the O-ring/seal is properly seated to prevent DEF leaks and crystallization.

   Install the new DEF quality sensor, ensuring the O-ring/seal is properly seated to prevent DEF leaks and crystallization.

9. 9

   Secure the mounting hardware and reconnect the electrical connector.

   Secure the mounting hardware and reconnect the electrical connector.

10. 10

    Reconnect the battery.

    Reconnect the battery.

11. 11

    Connect a diagnostic scan tool to the machine, clear the 17684 (F-4365-06) fault code, and run the engine to verify the code does not return and the DEF temperature reads accurately.

    Connect a diagnostic scan tool to the machine, clear the 17684 (F-4365-06) fault code, and run the engine to verify the code does not return and the DEF temperature reads accurately.