P0450Generic code

P0450 Code: Evaporative Emission Control System Pressure Sensor/Switch

The P0450 code indicates an electrical fault in the circuit of the fuel tank pressure sensor in the EVAP system. The main effect is that the EVAP leak test cannot run. Most of the time there are no other driving symptoms.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$40 to $300
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0450 code means

The fuel tank pressure (FTP) sensor measures the pressure or vacuum inside the fuel tank. The computer uses it in the EVAP leak test: it creates a vacuum and watches how long it takes to bleed off.

The sensor gets a 5 V reference and a ground from the computer and sends back a signal between roughly 0.5 and 4.5 V. A circuit fault can come from the sensor, the wiring or the power supply, and that is what the P0450 code reports.

Without a reliable FTP reading, the computer cannot run the EVAP test. The monitor stays incomplete and the vehicle cannot pass an emissions inspection. Many FTP sensors share the 5 V reference with other sensors, so a reference fault can set several codes at once. Look up the sensor guide to see how it is tested.

Always start with the simplest things: fuse, relay and connector. Then check power, ground and signal with the part still connected (using back-probes), and finally the continuity of each wire to the computer. Only if all of that checks out should you replace the component.

P0450 code symptoms

  • Check engine light on.
  • EVAP leak test cannot run.
  • Emissions monitor incomplete, so the vehicle cannot pass inspection.
  • Often there are no other driving symptoms.

Likely causes of the P0450 code

  1. Damaged or corroded connector. The most frequent cause.
  2. Cut or shorted wiring between the component and the computer.
  3. Failed sensor, open or internally shorted.
  4. Missing power reference. Check whether other sensors are also failing.
  5. Computer. Uncommon.

How to diagnose the P0450 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check the reference and ground with the key on (5 V, and less than 0.1 V of voltage drop on the ground).
  4. Measure the signal with the connector plugged in and see whether it changes with conditions.
  5. Do a wiggle test on the wiring.
  6. Check continuity to the computer.
  7. Remove the gas cap and confirm the sensor reads atmospheric pressure (close to 0).
  8. Command the EVAP valves with the scan tool and see whether the reading changes.

How to fix the P0450 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one (a leak or a blockage).
  • Clear the codes and complete a drive cycle so the monitor runs.

Technical reference data

  • With the gas cap off: about 2.5 V on many sensors.
  • Vacuum: the voltage drops. Pressure: the voltage rises.
  • Approximate values only: check the manufacturer data for your engine.

Brand-specific notes

The location of the tank pressure sensor changes by manufacturer, so find it before you start testing.

P0450 on GM

On GM vehicles the sensor is mounted on the fuel pump module.

P0450 on Ford

On Ford vehicles the sensor is often next to the canister.

P0450 on Toyota

On Toyota vehicles the sensor is often next to the canister.

Frequently asked questions about P0450

Can I drive with a P0450 code?
Yes. A P0450 code usually carries no immediate risk. The problem is the emissions inspection.
Do I have to replace the sensor?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor.
Will I pass the inspection with this code?
No. The check engine light being on, or the monitor being incomplete, keeps the vehicle from passing.
How much does it cost to fix P0450?
Roughly $40 to $300, depending on whether it is a connector, wiring or the sensor itself.
What does the P0450 code mean?
It is a generic OBD2 code for an electrical fault in the EVAP fuel tank pressure sensor circuit. The computer cannot get a usable reading to run the leak test.
What is the most common cause of P0450?
A damaged or corroded connector. Wiring faults and a failed sensor come after that.

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