Evaporative Emission Control System Pressure Sensor Low Input
The P0452 code means the vehicle's onboard diagnostic system has detected: Evaporative Emission Control System Pressure Sensor Low Input. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $80 - $300 (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 symptoms
- EVAP monitor will not complete
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Faulty fuel tank pressure sensor outputting low voltage Very High
- Open or shorted ground wire in FTP sensor circuit High
- Corroded or disconnected FTP sensor connector Moderate
- ECM internal fault on FTP input circuit Low
Step-by-Step Diagnostic Procedure
-
Check FTP sensor voltage on a scan tool -- voltage below 0.1V with cap off indicates a fault
-
Inspect the FTP sensor connector for corrosion, water intrusion, or bent pins
-
Measure voltage at the FTP sensor connector -- should have 5V reference and good ground
-
Check signal wire for short to ground using a multimeter with the sensor disconnected
-
Replace the FTP sensor if 5V reference and ground are confirmed good at the connector
Common Fixes by Vehicle
What techs usually find when diagnosing P0452 on specific vehicles — tap your vehicle for the fix and the exact part:
2004-2014 Ford F-150 5.4L Triton Easy DIY
The FTP sensor reads low voltage (below 0.5V) due to a wiring short to ground. Check the two-wire connector at the sensor for corrosion and check the harness for chafing against the frame rail. If the wiring is good, replace the FTP sensor (Motorcraft DY-1052).
Labor: 0.5-1 hour2007-2018 Chevrolet Silverado 5.3L Easy DIY
Low fuel tank pressure sensor input on GM trucks is often caused by water intrusion in the sensor connector under the truck. Unplug the connector, dry it out, and apply dielectric grease. If the reading does not normalize, the sensor is shorted internally and needs replacement.
Labor: 0.5-1 hour2006-2018 Dodge Charger 5.7L/3.6L Easy DIY
The EVAP pressure sensor signal wire loses ground continuity from a loose ground terminal at the body harness. Check the main EVAP ground at the left rear of the trunk area. Clean and tighten the ground terminal. If the sensor itself is shorted, it must be replaced as a unit.
Labor: 0.5-1.5 hoursFrequently Asked Questions
Can I drive with code P0452?
Yes. Low FTP sensor input does not affect engine performance or drivability. It will prevent the EVAP monitor from completing and cause an emissions test failure.
What voltage should the FTP sensor read?
With the gas cap off (atmospheric pressure), the sensor should read approximately 2.5V. With the cap on and the system sealed, it should vary between 1.0V and 4.0V during normal operation.
Can water damage cause P0452?
Yes. The FTP sensor connector is often located near the fuel tank where it is exposed to road spray. Water intrusion and corrosion are common causes of low voltage readings.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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