What Does P0450 Mean?
The fuel tank pressure (FTP) sensor in the EVAP system has a general malfunction. This sensor monitors the pressure/vacuum in the fuel tank during EVAP leak tests and normal operation. When the sensor fails, the PCM cannot monitor the EVAP system for leaks or proper purge operation. The driver will see a check engine light and the vehicle will fail emissions testing.
Common Causes
40%
Failed fuel tank pressure sensor (drift, stuck, or electrically open)
25%
Wiring issue in the FTP sensor circuit (open, short, or high resistance)
15%
Corroded or damaged connector at the fuel tank pressure sensor
10%
Fuel tank damage or deformation affecting sensor readings
10%
PCM sensor input circuit failure
Diagnostic Steps
1
Monitor the fuel tank pressure (FTP) sensor reading on scan tool live data. With the engine off and gas cap removed, the reading should be near atmospheric pressure (approximately 0 inH2O or the manufacturer's specified baseline).
2
Disconnect the FTP sensor connector and measure the 5V reference voltage and signal ground at the harness connector. Reference should be 4.9-5.1V, ground should be near 0V.
3
Measure the FTP sensor resistance/voltage at the sensor connector. Compare to manufacturer specifications for the current barometric conditions.
4
With the gas cap sealed and the engine running, command the EVAP purge valve on and monitor the FTP sensor for a vacuum reading change (should go negative/vacuum direction). No change suggests a stuck sensor.
5
Inspect the FTP sensor and its mounting location on the fuel tank for damage, cracks, or improper sealing that could allow false readings.
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
The fuel tank pressure (FTP) sensor in the EVAP system has a general malfunction. This sensor monitors the pressure/vacuum in the fuel tank during EVAP leak tests and normal operation. When the sensor fails, the PCM cannot monitor the EVAP system for leaks or proper purge operation. The driver will ...
The most common cause of P0450 (Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction) is: Failed fuel tank pressure sensor (drift, stuck, or electrically open)
Typical repair costs for P0450 range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The fuel tank pressure sensor is used for EVAP monitoring and does not affect engine performance or safety. Repair is required for emissions compliance and proper EVAP leak detection.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0450 to identify the root cause.
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Quick Info
Category
Powertrain
System
EVAP / Emissions System
Difficulty
Type
Generic (SAE)
Recommended Tools
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