What should be done before removing the fuel filter on a fuel-injected vehicle?

Relieving the fuel pressure is essential before removing the fuel filter on a fuel-injected vehicle. Fuel injection systems operate under high pressure, and if this pressure is not relieved before servicing the fuel system, it can lead to fuel spray, which is hazardous and can create a fire risk.

When the fuel filter is removed without relieving the pressure, gasoline can escape quickly, potentially causing spills and posing a danger to both the technician and the environment. To relieve the fuel pressure, you typically locate the fuel pump relay or fuse, remove it, and then start the engine to allow it to run until it stalls. This process effectively depressurizes the fuel system.

While draining the fuel tank or disconnecting the battery may appear relevant, they are not standard procedures specifically associated with fuel filter replacement. Removing spark plugs is unrelated to the fuel system and would not contribute to the safety or efficacy of replacing the fuel filter. Therefore, the correct preparatory action is to relieve the fuel pressure to ensure a safe maintenance process.