What Is a Fuel Tank Pressure Sensor?

A fuel tank pressure sensor is a small device that resides in an automotive fuel tank that measures the pressure within the gas tank. It uses this information to alert the car computer when there is a leak in the fuel system, causing stalling in the fuel pump, issues with the crankshaft, or other problems with fuel efficiency or fuel economy. When the engine control module is aware of a problem in the fuel pump assembly, the wiring harness will alert the computer of a trouble code and warning light will appear on your dash.

The EVAP

The fuel pressure sensor works in conjunction with a vehicle's evaporative control (EVAP) system, which captures any evaporated fuel before it leaves the fuel system. The sensor alerts the vehicle's computer to not only fuel tank leaks, but also to leaks in the EVAP system. If there is a problem with the fuel filter, pressure regulator, spark plugs, fuel injectors, fuel cap, coolant, or anything else in the control unit, the EVAP fuel tank pressure sensor will sense it and the check engine light will turn on.

Leak Testing

The fuel tank pressure sensor is always monitoring the pressure in the fuel tank or canister for potential leaks or fuel vapor. Pressure testing in the EVAP is performed periodically, typically after the vehicle has been sitting for a while (e.g., when the vehicle is first started up in the morning and fuel usage is just starting.

Benefits

Monitoring for leaks in the fuel tank and EVAP system can help vehicle owners recognize and repair leaks as soon as they begin occurring, saving fuel -- and gas money. It also helps vehicle owners to stay in compliance with federal and state regulations regarding emissions from fuel systems. These constant emissions tests will alert to a problem before symptoms of a bad fuel tank pressure sensor may even begin showing up.