Symptoms of a Bad Fuel Tank Pressure Sensor

Placed atop or inside of your fuel tank is a component called the fuel tank pressure sensor. Let’s take a look at what your fuel tank pressure sensor is and what it does, signs that it has gone bad, and how to fix it.

What is a fuel tank pressure sensor?

As its name suggests, this part is a pressure sensor for your fuel tank. Why is it important to know what the pressure inside your fuel tank is? There are a few important reasons:

• To identify leaks in the fuel system
• To alert you to a defective gas cap
• To signal the engine computer that the evaporative emissions system is operating properly
• To regulate the management of fuel consumption
• To maintain compliance with state and federal emissions regulations

The fuel tank pressure sensor does all this by monitoring the pressure, both positive and negative, inside your fuel tank. This sensor is an integral part of your car’s evaporative emissions system, also known as EVAP. The EVAP system is designed to keep all gasoline vapors within your car’s fuel system, after you have fueled it up at the gas station.

Signs of a bad fuel tank pressure sensor

If the sensor itself is bad, there’s really only one thing that will happen. The check engine light will come on.

Anytime this light comes on, you should get it checked out; a faulty sensor might not be so bad, but there are many other, more serious things that can trigger this light. It's best to be safe.

If your fuel system does have a pressure problem, you’ll see these signs:

• Your check engine warning light comes on
• Your fuel consumption increases noticeably
• A loss of power and acceleration
• Hard starting
• Stalling
• Black smoke coming out of tailpipe
• Gasoline dripping from tailpipe
• Your engine runs rough

If you notice any of these things happening, call your mechanic and have your car checked out right away.

How do you fix a bad fuel tank pressure sensor?

Your fuel tank pressure sensor cannot be repaired if it has gone bad. It must be replaced. Given the dangers of working with automotive electronics and fuel systems, it’s best for most people to leave this job to a professional repair shop.