P0451 on Mazda
Evaporative Emission System Pressure Sensor/Switch Range/Performance
P0451 on Mazda vehicles indicates evaporative emission system pressure sensor/switch range/performance. Au7o has documented this code across 1 Mazda model — most commonly on Mazda3. This code means the PCM detected that the EVAP system pressure sensor (fuel tank pressure sensor) is producing readings that are erratic, noisy, or outside the expected range. This sensor monitors pressure and vacuum in the fuel/EVAP system to detect leaks and manage vapor flow. A range/performance fault undermines the system's ability to run leak tests, which is an emissions issue. It usually triggers only the check engine light without affecting how the car drives. Typical repair costs on Mazda range from $80 to $250, depending on the specific model and root cause.
Common Causes of P0451
- •Faulty fuel tank/EVAP pressure sensor
- •Loose or faulty gas cap causing abnormal pressure
- •Damaged wiring or connector at the sensor
- •Blocked, kinked, or leaking EVAP hoses
- •Sensor contamination or internal fault
- •Failing PCM (less common)
P0451 on Mazda by Model
Mazda Mazda3(1 issue)
- EVAP Purge Valve Failure and Fuel Odor2014-2018
Third-generation Mazda3 models with the SkyActiv 2.0L and 2.5L engines experience premature EVAP canister purge valve failure. The valve can stick open, flooding the engine with fuel vapors and causing rough idle, stalling, and a strong fuel smell. Conversely, a stuck-closed valve prevents the EVAP system from purging, triggering check engine lights for evaporative system leak codes.
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What does P0451 mean on Mazda?▼
P0451 stands for "Evaporative Emission System Pressure Sensor/Switch Range/Performance." This code means the PCM detected that the EVAP system pressure sensor (fuel tank pressure sensor) is producing readings that are erratic, noisy, or outside the expected range. This sensor monitors pressure and vacuum in the fuel/EVAP system to detect leaks and manage vapor flow. A range/performance fault undermines the system's ability to run leak tests, which is an emissions issue. It usually triggers only the check engine light without affecting how the car drives. On Mazda specifically, this code is documented across 1 model.
What causes P0451 on Mazda vehicles?▼
Common causes on Mazda: Faulty fuel tank/EVAP pressure sensor, Loose or faulty gas cap causing abnormal pressure, Damaged wiring or connector at the sensor, Blocked, kinked, or leaking EVAP hoses, Sensor contamination or internal fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0451 on a Mazda?▼
Repair costs on Mazda range from $80 to $250, depending on the specific model and root cause.
Which Mazda models have P0451 documented?▼
Au7o has documented P0451 on 1 Mazda model: Mazda3.