Jeep Liberty P0453 - Fuel Tank Pressure Sensor/Switch To High

The evaporative emission control system (EVAP), used by Jeep Liberty, moves fuel vapors between the fuel tank and filler neck and then sends them to engine for combustion.  If the fuel tank pressure is too high P0453All is well and the engine light goes on.

Your Liberty will not be in danger if the trouble code you only have P0453.  The EVAP system controls the movement of fuel vapor.  It doesn't matter if it does that, or not. This has no impact on how your engine works.  We don't endorse ignoring this code.

The EVAP system does not work all the time.  It uses a  valve to open and close the system to release fuel vapor into the engine to be burned off.

It is the fuel tank pressure sensor that detects excessive pressure.  This sensor measures air pressure within the tank. It does not measure fuel pressure.  If it does so, then P0453 will be thrown.  The fuel tank pressure sensor, also known as the fuel pump pressure sensor, is usually located on top of your gas tank or fuel pump.

The opposite of this code is P0452, which is thrown whenever the system pressure is too low.

P0453 Symptoms:  Jeep Liberty

There are usually no symptoms that can be associated with the code.  The check engine light will illuminate (that’s why you’re here).

You may only notice the fuel smell.  If the EVAP isn't working properly to remove the fuel vapor from the air, the system will look for other routes.

The causes

Below are some more frequent causes of P0453.

• Charcoal canister Clogged vent valve
• Pressure sensor in fuel tank damaged (sensor, or the wiring)
• Damaged fuel tank
• PCM/ECM (highly unlikely)

Diagnostics for P0453 on the Jeep Liberty

Diagnosing P0453 in your Liberty can be challenging if you don’t have a scan tool that is capable of reading the fuel pressure sensor data or capable of commanding the vent valve to open and close.

Here are some things you can do at home

• If you happen to notice the sound of air escaping when you take your Liberty’s gas cap off, that is a telltale sign that the vent valve is bad, or the charcoal canister is bad(it’s pressure leaving the gas tank).  Once you have driven for some time, turn off the gas cap and go somewhere else.  It’s hard to notice the sound when you’re at a noisy gas station.
• Examine the wiring connecting to the fuel pressure sensor. If it is damaged or frayed, you should inspect it.  If it isn’t then the only way to really diagnose it is with a professional mechanic’s scanner.  It can be difficult to look at the tank without dropping it.

What a Mechanical Engineer Will Do

• To determine if the sensor detects vacuum, a mechanic will take data from the fuel pressure sensor.
• You can also tell the vent valves to open or close.  You can also hear the engine running depending on your vehicle's year.

A mechanic can inspect the wiring leading to the fuel pressure sensor if the fuel tank pressure is not within the specifications.  The fuel pressure sensor must be replaced if it is not working as expected.

If the vent valve is on and the pressure sensors are fine, the charcoal canister needs to be replaced.  If the vent valve doesn’t come on, it will need replacement in order to clear P0453.

If it looks good, the PCM could have a problem.

Jeep Liberty P0453 Conclusion

That’s pretty much it.  While there are only a couple of common things that’ll cause P0453, there it can be tough to diagnose it without the right equipment.  It’s not going to leave you stranded on the side of the road either.  You're going to fix your Liberty.