P0451: Evaporative Emission System Pressure Sensor/Switch A Circuit Range/Performance
What to do
Driveable with no symptom. Ask whether the sensor's line was checked as well as the sensor.
What this code means
The fuel tank pressure sensor is reading within its electrical range but not plausibly — failing to respond when the system is sealed, or reporting pressures the tank could not physically be at.
A blocked or kinked sensing line produces exactly this while the sensor itself is healthy, and it is easier to check than the sensor is to replace.
Likely causes
Start here
- Faulty fuel tank pressure sensor · moderate
- Blocked or kinked sensor line · moderate
Less common
- Sensor drifted out of calibration · moderate
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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