Evaporative Emission Control System Pressure Sensor Range/Performance
What does P0451 mean?
The P0451 code means the vehicle's onboard diagnostic system has detected: Evaporative Emission Control System Pressure Sensor Range/Performance. This is a low severity code.
Common Symptoms
- Check Engine Light illuminated
- No noticeable drivability symptoms
- Erratic fuel gauge behavior in some vehicles
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Failing fuel tank pressure sensor giving erratic readings Very High
- Intermittent wiring issue in FTP sensor circuit High
- EVAP system leak affecting pressure readings Moderate
- Loose or damaged gas cap Moderate
Step-by-Step Diagnostic Procedure
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Monitor FTP sensor voltage on a scan tool during EVAP system self-test -- look for erratic or jumping values
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Compare sensor readings with the gas cap on vs. off -- should show a clear change in voltage
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Wiggle the FTP sensor connector and wiring while monitoring live data for intermittent drops
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Perform a smoke test to rule out EVAP system leaks that may affect pressure readings
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Replace the FTP sensor if readings are inconsistent during testing
Frequently Asked Questions
Can I drive with code P0451?
Yes. This code indicates the fuel tank pressure sensor readings are inconsistent, but it does not affect engine performance. It will cause an emissions test failure.
What causes erratic FTP sensor readings?
The most common cause is a failing pressure sensor with a worn internal element. Intermittent wiring connections and EVAP leaks can also produce inconsistent readings.
Is P0451 related to fuel gauge problems?
On some vehicles, the FTP sensor and fuel level sender share the same module. A failing module can cause both P0451 and inaccurate fuel gauge readings.