Case IH 17909 (F-3511-05) - ECU – Engine Control Module (ECM / ECU): ECM 5 volt sensor supply 3 under voltage failure

The Engine Control Module (ECM) has detected that the 5-volt reference circuit #3—which supplies power to a specific group of engine sensors—has dropped below the acceptable voltage threshold.

• VESTRUM CVX
• MX Magnum Series
• TG Series
• Steiger Series
• Farmall Series

1. 1

   Verify battery voltage is sufficient and there are no excessive voltage fluctuations causing the ECM to drop the 5V output.

2. 2

   Inspect the wiring harness and connectors on the 5V Supply 3 circuit for chafed wires, broken connector locks, or pushed-out pins.

3. 3

   Perform a sensor isolation test by disconnecting sensors on the 5V Supply 3 circuit one at a time to see if the 5-volt reference returns to normal (indicating an internally shorted sensor).

4. 4

   Perform a harness short-to-ground test with sensors and ECM disconnected, checking for continuity between the 5V Supply 3 wire and chassis ground.

1. 1

   Connect the Electronic Service Tool (EST)

   Verify if the fault code 17909 is currently active or stored as inactive.

2. 2

   Inspect and Repair Wiring

   If the visual inspection or multimeter tests reveal a short to ground in the wiring harness, repair the damaged section of the wire or replace the affected connector pigtail. Ensure connector locks are securely holding the pins.

3. 3

   Replace Faulty Sensor

   If the sensor isolation test proves a sensor is pulling down the voltage, replace the internally shorted sensor.

4. 4

   Test the ECM

   If the wiring harness is completely intact (no shorts to ground) and all sensors are unplugged, but the ECM is still not outputting 5 volts on the Supply 3 pin, the ECM has suffered an internal driver failure.

5. 5

   Clear Codes and Retest

   After repairing the harness, replacing the sensor, or replacing the ECM, clear the fault codes using the EST and run the engine to verify the 5V supply remains stable and the code does not return.