Evaporative Emission Control System Pressure Sensor Malfunction
The P0450 code means the vehicle's onboard diagnostic system has detected: Evaporative Emission Control System Pressure Sensor Malfunction. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $350 (parts and labor)
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 issues
- Failed emissions inspection
- Fuel tank pressure readings erratic on scan tool
Probable Causes (Ranked by Likelihood)
- Failed fuel tank pressure sensor (FTP) Very High
- Wiring issue in FTP sensor circuit High
- Corroded connector at the pressure sensor Moderate
- ECM fault in FTP sensor input circuit Low
Step-by-Step Diagnostic Procedure
-
Use a scan tool to monitor fuel tank pressure sensor voltage -- it should read approximately 2.5V with the cap off (atmospheric pressure)
-
Inspect the FTP sensor connector for corrosion or damage
-
Check signal and ground wiring from the FTP sensor to the ECM for continuity
-
Compare FTP sensor readings with a known-good mechanical gauge
-
Replace the FTP sensor if readings are erratic or out of range
Common Fixes by Vehicle
What techs usually find when diagnosing P0450 on specific vehicles — tap your vehicle for the fix and the exact part:
2005-2014 Ford F-150 5.4L/4.6L Easy DIY
The fuel tank pressure sensor (FTP) on Ford trucks fails from exposure to fuel vapors and moisture. Located on top of the fuel tank or on the EVAP canister, it reads erratic pressure values. Replace with Motorcraft DY-1052 sensor. No need to drop the tank on most models.
Labor: 0.5-1 hour2006-2016 Chevrolet Silverado/GMC Sierra 5.3L Moderate DIY
The fuel tank pressure sensor on GM trucks is integrated into the EVAP canister vent solenoid assembly. If the sensor reads out of range, replace the entire vent solenoid assembly (ACDelco 214-2338). Located under the truck near the fuel tank. Clean connectors before installing.
Labor: 1-1.5 hours2003-2015 Dodge Ram 1500 5.7L Hemi Moderate DIY
The EVAP system pressure sensor on the Hemi Ram develops erratic readings from a corroded ground wire at the tank. Check the ground wire at the fuel tank strap bolt first. Clean and re-secure the ground. If the sensor still reads erratically, replace the FTP sensor on the fuel pump module.
Labor: 1-2 hoursFrequently Asked Questions
Can I drive with code P0450?
Yes. The fuel tank pressure sensor monitors the EVAP system but does not affect engine operation. You will fail an emissions test with this code present.
Where is the fuel tank pressure sensor located?
The FTP sensor is typically mounted on top of the fuel tank or on the fuel pump module assembly. Access usually requires lowering the tank or removing a rear seat access panel.
How much does a fuel tank pressure sensor cost?
The sensor itself typically costs $40-$120 depending on the vehicle. Labor to access and replace the sensor can add $60-$230 due to fuel tank access requirements.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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