* Blown fuse: This is the most common cause. Check the fuse box for a blown fuse related to the fuel pump. The fuse box location varies by vehicle; consult your owner's manual.
* Faulty relay: The fuel pump is often controlled by a relay. A bad relay will prevent power from reaching the pump. Locate the fuel pump relay (again, your owner's manual is helpful) and test it or replace it with a known good one.
* Wiring problems: A broken, corroded, or damaged wire in the circuit leading to the fuel pump can interrupt power. This may require tracing the wiring harness to find the fault.
* Faulty fuel pump control module (PCM/ECM): In some vehicles, the computer controls the fuel pump. A problem with the PCM/ECM can prevent it from sending power to the pump. This is less common but can be diagnosed with a scan tool.
* Inertia switch: Some vehicles have an inertia switch that cuts power to the fuel pump in a collision to prevent fuel leaks. Check if this switch is tripped (it's usually under the dashboard or in the engine compartment).
* Security system issue: In some cars with sophisticated security systems, a problem with the system might prevent the fuel pump from engaging.
* Low voltage: Insufficient voltage from the battery can prevent the fuel pump from operating. Test the battery voltage.
To diagnose the problem, systematically check these items. If you're not comfortable working on your car's electrical system, take it to a qualified mechanic. Improperly working on your car's electrical system can be dangerous.
