OBD-II Code · Emissions
P0451
EVAP Fuel Tank Pressure Sensor Range
Severity
low
Lowest on our scale. Fix it when convenient.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$100–$300
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Tank pressure sensor out of range.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Likely causes
- Failed sensorMost common
- Wiring
Read the full diagnostic procedureP0451 is a sensor range/performance code on the fuel-tank pressure sensor (FTPS, sometimes called FTP or EVAP pressure sensor).
P0451 is a sensor range/performance code on the fuel-tank pressure sensor (FTPS, sometimes called FTP or EVAP pressure sensor). The sensor reports tank pressure to the ECU; the ECU watches it during normal driving and during EVAP leak tests to verify that pressure changes match what should be happening. P0451 trips when the sensor reading is technically inside the electrical range (so it's not P0452 or P0453) but is drifting, sticking, or behaving in ways that don't make physical sense — for example, not responding to fill-up pressure changes, or reporting flat values during a purge cycle. The diagnostic move is scan-tool the FTPS live data while driving and watching for normal pressure swings (a small vacuum builds as fuel is consumed; a brief positive pressure occurs at fill-up). If the sensor is flat-lined or stuck, it's the sensor. If it tracks but with implausible values, check the connector and wiring before condemning the sensor. The fuel cap is still a worthwhile $5-30 check because a cap leak that prevents the system from holding pressure can throw P0451 on platforms where the ECU expects to see a sealed-tank pressure signature.
Vehicle-specific patterns2012+ Hyundai/Kia is the dominant P0451 platform in shop work — Sonata, Elantra, Optima, Forte, Sportage, Tucson, Santa Fe — these vehicles use an FT…
- 2012+Hyundai/Kia is the dominant P0451 platform in shop work — Sonata, Elantra, Optima, Forte, Sportage, Tucson, Santa Fe — these vehicles use an FTPS that has a well-documented failure rate; the sensor sits on top of the fuel tank and is accessed by either dropping the tank or, on some platforms, a service access panel under the rear seat. Sensor cost is typically $80-150, labor is the bigger variable.
- 2005-2015Toyota/Lexus rarely throws P0451 unless the sensor connector has corroded.
- 2003-2010Ford 4.6L can throw P0451 when the FTPS connector at the tank gets road-salt corrosion.
- 2007-2014GM trucks throw P0451 occasionally but it's not their dominant pattern (vent solenoid dominates).
- 2008-2015VW/Audi don't typically throw P0451 because they use the LDP method rather than a tank-mounted FTPS for leak detection. Repair range: $80-150 sensor, plus 0.5-2.0 hours labor depending on tank access.
Look up another code
P0451 — frequently asked
What does a P0451 code mean?
Tank pressure sensor out of range.
What causes a P0451 code?
Common causes: Failed sensor; Wiring.
What are the symptoms of a P0451 code?
Typical symptoms: Check engine light.
Is it safe to drive with a P0451 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $100-$300.
How do I diagnose a P0451 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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