Mazda Miata P0453: Too high fuel tank pressure sensor/switch

Mazda Miata employs an evaporative emission control (EVAP), which moves fuel vapors between the fuel tank, fuel filler neck, then to the engine.  The fuel tank's pressure can rise to dangerous levels. P0453The engine light will turn on after the key is thrown.

Your Miata will not fail if the trouble code is only P0453.  The EVAP is responsible for transferring fuel vapor.  It does not matter whether it's doing this or not. The engine will still run as normal.  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.

This sensor detects if the fuel tank pressure is too high.  It measures the air pressure inside the tank and not the fuel pressure.  When it does, the P0453 signal is sent.  The fuel tank pressure sensor, also known as the fuel pump pressure sensor, is usually located on the 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:  Mazda Miata

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 your EVAP system doesn't properly remove fuel vapor it will seek other escape routes.

The causes

Below are some more frequent causes of P0453.

• Charcoal canister Clogged vent valve
• Pressure sensor in fuel tank damaged (sensor or wiring).
• Fuel tank damage
• PCM/ECM (highly unlikely)

Diagnose P0453 with the Mazda Miata

Diagnosing P0453 in your Miata 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 Miata’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).  You can open the gas valve by driving for awhile.  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.  This is difficult because you may need to remove the tank from your vehicle to be able to examine it.

How a mechanic will do it

• The data of the fuel pressure sensor will be captured by a mechanic to determine whether it detects any vacuum.
• You can also tell the vent valves to open or close.  This can be heard depending on which year and model of the vehicle.

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, the pressure sensor should be fine. Then 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.

Mazda Miata P0453

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 be able to fix your Miata.