* Faulty Fuel Level Sensor: This is the most common culprit. The sensor in the fuel tank measures the fuel level and sends that information to the instrument cluster. If the sensor is malfunctioning (dirty, damaged, or failing), it might provide inaccurate readings, even resetting to empty after a fill-up.
* Bad Fuel Pump Module: The fuel pump module often houses the fuel level sensor. A problem with the entire module can lead to inaccurate gauge readings or complete failure.
* Wiring Issues: Damaged, corroded, or loose wiring between the fuel level sensor and the instrument cluster can disrupt the signal, leading to erratic gauge behavior.
* Instrument Cluster Problem: While less likely, a problem within the instrument cluster itself could cause the gauge to malfunction. This could be a faulty gauge, a failing circuit board, or other internal component issues.
* Air in the Fuel System: Though less common, if there's significant air in the fuel lines, it could temporarily affect the fuel level sensor's reading. This is more likely to cause fluctuating readings rather than a complete reset, but it's possible.
Troubleshooting Steps:
1. Check for Obvious Problems: Look for any obvious damage to the fuel tank area, wiring near the tank, or the instrument cluster itself.
2. Have the Fuel System Diagnosed: A mechanic can use a scan tool to check for diagnostic trouble codes (DTCs) related to the fuel level sensor or fuel system. This will point towards the most likely problem.
3. Inspect the Fuel Level Sensor (Advanced): This often requires dropping the fuel tank, which is a more involved process best left to a professional mechanic. They can visually inspect the sensor for damage and potentially test it for proper function.
Don't ignore this problem. An inaccurate fuel gauge can lead to running out of gas unexpectedly, which can be inconvenient and potentially dangerous. Getting it diagnosed and repaired is crucial.
