P0453: EVAP System Pressure Sensor/Switch High Input
Key takeaways
- P0453 means the fuel tank pressure sensor's signal went above the range the engine computer accepts.
- It's an emissions code: the car is safe to drive, but it will fail an emissions or plug-in inspection.
- An open ground or signal wire, a failed sensor, and real pressure trapped in the tank by a blocked vent or liquid fuel in the vapor lines are the usual causes.
- Mazda has a bulletin for 2013–2015 CX-5s setting P0452 or P0453 right after startup, and Lexus has one for 2010–2014 RX 350s with liquid fuel in the EVAP system.
- Most P0453 repairs at a US independent shop run $100–$400; a charcoal canister soaked with fuel is the expensive outcome at $300–$800.
What P0453 means
The sensor that measures pressure in your fuel tank is sending a signal that’s too high.
Scanners call it Evaporative Emission System Pressure Sensor/Switch High Input. The EVAP system traps fuel vapor from the tank in a charcoal canister and later burns it in the engine. To test that system for leaks, the computer seals it and watches the fuel tank pressure sensor. The sensor gets a 5-volt reference and a ground, and returns a voltage that follows tank pressure. P0453 sets when that voltage sits above the range the computer expects. Usually that’s an electrical fault, but sometimes the tank really is holding pressure it can’t vent.
Is it safe to drive?
Yes. P0453 affects emissions monitoring, not how the engine runs. You will fail an emissions or plug-in inspection, and while the light is on for this, a second fault won’t get your attention.
What changes the answer: a strong raw-fuel smell or fuel dripping under the car. A liquid leak is a fire risk, not an emissions issue; park it and see what a gas smell means. A rough idle or hard start right after filling up points to liquid fuel in the vapor lines; get that checked within the week.
Causes, ranked
| Cause | How you confirm it | Typical cost (US independent shop, 2026) |
|---|---|---|
| Wiring or connector at the sensor (open ground, signal shorted to reference) | Reading pinned high on a scan tool; damaged, corroded or loose plug on the tank or canister | $100–$250 |
| Failed fuel tank pressure sensor | Reference and ground good, but the reading stays high with the cap off | $150–$400; more when the tank has to come down |
| Blocked or kinked vent line, or vent valve stuck closed | Reading drops to normal when the cap comes off; pump nozzle clicks off early | $100–$350 |
| Liquid fuel in the EVAP lines or a fuel-soaked canister | History of topping off; fuel in the vapor hoses; rough idle after refueling | $300–$800 |
| Software calibration on specific models | A manufacturer bulletin matches your car and code | Often $0 under warranty; $100–$200 otherwise |
What to check first
- Read every stored code. P0453 with P0452 history points to an intermittent connection. P0453 with P0446 points to the vent side.
- Look at the key-on reading with the cap off. A good sensor reads close to zero. If the reading stays pinned high, it’s electrical or the sensor. If it drops to zero when the cap comes off, the tank really was pressurized and the vent path is the problem.
- Check for a bulletin before buying parts. The pattern is small but specific: Mazda covers 2013–2015 CX-5s that set P0452 or P0453 right after startup, Subaru moved an engine harness ground point on some 2012–2014 WRX and Forester models to stop false EVAP codes, and Lexus has bulletins for some Canadian-built 2010–2014 RX 350s with liquid fuel in the EVAP system, which can also cause an intermittent rough idle.
- Inspect the sensor connector and harness. The sensor sits on top of the tank or near the canister, where road water and salt get in.
- Stop topping off the tank. If fuel has reached the vapor lines, filling past the first click keeps making it worse. See our gas cap guide for the cap side of things.
- Clear it and drive. If it was a one-off, the light stays off after a few drive cycles.
What it costs
The cheap outcome is a connector repair or a software update, from free under warranty to $100–$250. The common outcome is a new tank pressure sensor at $150–$400, more if the tank has to come down, or a vent line or valve at $100–$350. The expensive outcome is a charcoal canister soaked with fuel, $300–$800. Watching the sensor reading with the cap on and off tells you which one you have before you pay for parts. If you’re unsure where to start, ask our AI mechanic with your car and code list.
Related codes
P0452 is the same sensor reading too low and P0451 is it reading implausibly. P0453 with leak codes like P0455 or P0456 usually means the sensor needs testing before the leak search. If the light keeps coming on and going off, that fits a connector that gets wet.
What owners report to NHTSA
3 complaints filed with NHTSA mention P0453, 2 of them since 2015, across 3 different models. The component owners most often filed it under: fuel/propulsion system.
Manufacturer service bulletins that name P0453
4 technical service bulletins and manufacturer communications filed with NHTSA mention P0453, from 3 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:
- MAZDA CX-5 (2013, 2014, 2015), bulletin 10098213: SOME VEHICLES MAY EXHIBIT A CONDITION WHERE THE CHECK ENGINE LIGHT ILLUMINATES IMMEDIATELY AFTER THE ENGINE IS STARTED AND DTC P0452:00 AND/OR P0453:00 IS STORED IN MEMORY. P0452:00 - FUEL TANK PRESSURE SENSOR LOW INPUTP…
- SUBARU WRX (2012, 2013, 2014), bulletin 10092491: "THIS SERVICE INFORMATION BULLETIN REVIEWS A DESIGN CHANGE TO THE ENGINE WIRING HARNESS TO ELIMINATE IMPROPER DIAGNOSIS OF THE EVAPORATIVE LEAK CHECK MODULE (ELCM) BY THE ECM WHICH COULD SET DIAGNOSTIC TROUBLE CODE (DTC)…
- LEXUS RX350 (2010, 2011, 2012, 2013), bulletin 10133703: Some TMMC built 2010 ? 2014 model year RX 350 vehicles may exhibit one or more of the following conditions due to liquid fuel in the Evaporative Emissions system (EVAP system): MIL ?ON? with Diagnostic Trouble Code (DTC)…
Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.
Frequently asked questions
Can a loose gas cap cause P0453?
Not usually. A loose cap lets pressure out, which would pull the reading toward zero, not push it high. P0453 is most often electrical. Check that the cap clicks anyway, then move on to the sensor and its wiring.
Is P0453 always a bad fuel tank pressure sensor?
No. An open ground wire or a signal wire shorted to the 5-volt reference gives the same high reading. So can a tank that really is pressurized because the vent is blocked. Watch the reading with the cap off before buying the sensor.
Can I drive with a P0453 code?
Yes. The engine runs normally. If you also get a rough idle or a hard start after filling up, liquid fuel may be in the vapor lines; stop topping off and have it checked within the week.
Why does P0453 show up after I fill the tank?
Overfilling can push liquid fuel into the vapor lines and the charcoal canister. That traps pressure in the tank and can soak the canister. Stop at the first click of the pump nozzle.