Case IH 518653-04 - ICM – ICM: Fuel Level Sensor Circuit - Voltage Below Normal, or Shorted to Low Source (Short to Ground)

The system is detecting that the voltage returning from the fuel level sensor is lower than the acceptable threshold, meaning the signal wire is likely grounding out against the chassis or the sensor itself has failed internally.

• MAGNUM AFS Connect
• Magnum AFS Connect series
• Puma series

1. 1

   Inspect the wiring harness running from the ICM to the main fuel tank for chafed wires rubbing against the frame that could cause a short to ground.

2. 2

   Disconnect the plug at the fuel level sensor and inspect for water intrusion, dirt, or severe pin corrosion, which can bridge the connections and cause a short.

3. 3

   With a multimeter, check the signal wire for continuity to ground while disconnected from the sensor. If there is continuity, the wiring harness is shorted and needs repair.

4. 4

   If the wiring harness tests fine, test the internal potentiometer of the fuel level sensor, as it has likely failed and shorted internally.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the fuel level sensor assembly on the top of the main fuel tank.

3. 3

   Remove the Sensor

   Disconnect the electrical harness. Remove the mounting screws (typically 5 hex washer head screws) securing the sensor to the tank.

4. 4

   Clean the Area

   Carefully pull the sensor out and clean the mating surface on the tank. Ensure no debris falls into the fuel tank.

5. 5

   Install New Parts

   Place a new gasket (do not reuse the old one) onto the tank opening. Insert the new fuel level sensor and secure it with the mounting screws.

6. 6

   Reconnect

   Plug the electrical harness back into the sensor and reconnect the battery.

7. 7

   Clear Codes

   Turn the key to the ON position. Verify that the fuel gauge registers a level, and use the diagnostic menu in the AFS Pro monitor (or a dealer service tool) to clear the inactive 518653-04 fault code.