Evaporative Emission Control System Pressure Sensor Range/Performance
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.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $600 (parts and labor; the high end applies when the sensor is integrated into the in-tank fuel pump module and the tank must be dropped to replace it)
A cracked or loose gas cap causes 60%+ of EVAP codes. This $8 replacement clears P0442, P0455, and P0457 more often than any other repair.
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If a new gas cap does not clear it, the leak is somewhere in the EVAP plumbing. A smoke machine finds the exact leak -- a cracked hose, bad seal, or stuck vent valve -- in minutes instead of guessing at parts.
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Clear the code after the repair. If the light stays off after 50 miles, you just saved $200+ in shop fees.
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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
-
Monitor FTP sensor voltage on a scan tool during EVAP system self-test -- look for erratic or jumping values
-
Verify the FTP sensor responds to pressure: with the cap off it should read atmospheric (about 2.5V / 0 inH2O); then apply a small hand vacuum and pressure to the sensor port (or run the EVAP self-test) and confirm the voltage moves smoothly and predictably -- a stuck, erratic, or non-responsive reading indicates a bad sensor
-
Wiggle the FTP sensor connector and wiring while monitoring live data for intermittent drops
-
Perform a smoke test to rule out EVAP system leaks that may affect pressure readings
-
Replace the FTP sensor if readings are inconsistent during testing
Common Fixes by Vehicle
What techs usually find when diagnosing P0451 on specific vehicles — tap your vehicle for the fix and the exact part:
2004-2018 Ford F-150/Explorer 4.6L/5.4L/3.5L moderate DIY
P0451 indicates the fuel tank pressure (FTP) sensor is reading outside of its expected range. On Ford trucks, the FTP sensor is mounted on top of the fuel tank. Fuel slosh and erratic readings are common when the sensor cracks. Replace with Motorcraft DY-1350 FTP sensor. Access through the bed or by dropping the tank.
Labor: 1-2 hours2010-2020 Chevrolet Silverado/GMC Sierra 5.3L moderate DIY
GM trucks use a fuel tank pressure sensor integrated into the fuel pump module. Erratic readings trigger P0451. Before replacing the sensor, check for a loose or corroded ground wire at the frame rail near the fuel tank. Clean the ground and retest. If the sensor is faulty, it can be replaced separately (ACDelco 13502903) without replacing the full fuel pump module.
Labor: 1-2 hours2009-2020 Dodge Ram 1500/Durango 5.7L Hemi moderate DIY
The EVAP pressure sensor on Dodge/Ram trucks is located on the fuel tank. Water intrusion into the connector causes erratic readings. Check the connector for moisture and corrosion first. If the sensor output fluctuates wildly on a scan tool (more than 1 inH2O at rest), replace with Mopar 68164-850AA or a Dorman equivalent.
Labor: 1-2 hoursFrequently 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.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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