P1450 Code in Ford Vehicles (Causes and Fix)

The P1450 is an OBD-II generic code indicating an issue controlling vacuum in the fuel tank during driving. This engine trouble code specifically means “Unable To Bleed Up Fuel Tank Vacuum” and sets when the powertrain control module (PCM) detects higher than expected vacuum in the fuel tank while the vehicle is in motion. This code pertains to the evaporative emissions control system. Common causes for P1450 are a stuck open purge valve not closing properly, an EVAP canister that is defective and failing to absorb fuel vapors, or a faulty fuel tank pressure sensor providing inaccurate readings to the PCM. The engine computer monitors fuel vapor levels by opening and closing the EVAP purge valve, so if this valve malfunctions, it can cause the P1450 code to set.

The P1450 code can leave Ford drivers feeling uneasy. It tells you something is up with the evaporative emissions system vent valve – not good. Ignoring this could mean staring at a glowing check engine light and watching your fuel economy drop.

But don’t panic. Annoying? Sure. Expensive to repair? Not usually. With basic skills and tools, you can solve this and get back to smooth cruising fast.

Let’s explore why P1450 happens and how to banish it for good. Think of this guide as your new best friend when that frustrating engine code pops up.

You can also read my guide on causes of P0171 Code.

Some Key Insights for You
  • P1450 indicates an issue controlling vacuum in the fuel tank while driving. It pertains to the evaporative emissions system.
  • Symptoms are just the check engine light, though some report issues starting the car after refueling.
  • Steps to troubleshoot include inspecting hoses for cracks/debris, testing the purge valve, checking the vent valve and canister, inspecting the fuel cap, and testing the pressure sensor.
  • A vacuum pump and multimeter are needed to properly test components.
  • The purge valve is the most common culprit for P1450.

My Personal Experience With P1450 Code

My brother drives an older Ford F-150 pickup. A few months ago his check engine light came on with a P1450 code. After some research, we tested the purge valve by connecting a hand vacuum pump.

It wouldn’t hold pressure, indicating it was stuck open. We ordered a new valve online for $30 and installed it in about 30 minutes. Cleared the code and no issues since!

What Are The Symptoms of P1450 Code?

P1450 code does not interrupt driving like other trouble codes. The only noticeable symptom of the P1450 code in Ford vehicles is that the check engine light turns on. i won’t cause any vehicle performance issues like rough idling etc.

However, some users report that due to P1450, your Ford vehicle might face issues with starting. I have stated this reason in my article on car not starting after getting gas.

This happens when the purge valve is stuck open, excessive fuel vapors enter the engine cylinder. When there is excessive fuel in the air-fuel mixture, fuel will not be completely burnt, due to which the car takes several tries to start after it is refilled with the fuel.

Also, if an excessive vacuum is developed inside the EVAP system it can cause the fuel tank to collapse. So, it is important to troubleshoot the P1450 trouble code even if your vehicle is running fine.

To understand how exactly EVAP system works, you can my guide on car sputtering after filling gas.

Possible Causes of P1450 Code in Ford

1. Kinks or Bends, Crack, Debris in the Fuel Vapor Hoses/Tubes

Kinks or Bends, Crack, Debris in the Fuel Vapor Hoses/Tubes

Troubleshooting the P1450 trouble code in your Ford truck starts with a close look at the EVAP system. Carefully check all the hoses, wires and connections before removing any parts.

A few things to inspect are:

  • The EVAP canister tube for blocks or sharp bends
  • The fuel vapor elbow on the EVAP canister for dirt or gunk
  • The vacuum hose from the purge valve to the engine air intake

Any kinks in the hoses can cause issues by lowering the pressure too much. This makes a big vacuum in the EVAP system.

Also check around the hoses and tubes connecting to the EVAP for debris or junk that should not be there.

A visual check of the whole EVAP system is a good first step when the P1450 code comes on. Finding any dirty or damaged parts makes fixing the problem easier.

How to detect?

You can use a UV light across the car’s underside, following the system’s path from the engine section to the rear fuel tank to inspect the EVAP system connections. Any smoke oozing from the system will lighten up in the ultraviolet light.

You might also need to perform a smoke test using a smoke machine to detect any leaks in EVAP hoses before proceeding further. For this, you can go to your nearby mechanic to have a professional smoke test done for the EVAP system.

To check the dirt or debris in the hoses, blow the air through them and see if there is some restriction that requires more force.

2. EVAP Purge Valve Stuck Open

EVAP Purge Valve Stuck Open

The EVAP purge valve plays an important role in preventing emissions from your vehicle. This valve is either near the engine’s throttle body or under the car by the fuel tank.

The EVAP purge valve works like a solenoid to help harmful gases exit safely. It connects to the air intake system.

When the EVAP purge valve opens, vacuum pulls outside air through the vapor storage canister. This moves extra fuel vapors from the canister into the air intake. Then the vapors burn along with the air and gas mixture in the engine. Keeping these emissions from getting out is helpful for the environment.

If the EVAP purge valve gets stuck open, it can trigger the P1450 error code. This lets you know the valve may not be closing like it should after purging vapors from the canister.

How to diagnose?

You can easily diagnose the purge valve by these steps:

  • Turn off the ignition switch.
  • Locate purge valve with the help of EVAP system diagram in owner’s manual
  • Remove the purge valve
  • Take a vacuum pump tester and connect it with the port on the purge valve that goes to the intake manifold of the engine.
  • If the valve is not holding the vacuum, it means it is faulty.

The following video will help you a lot.

3. Canister Vent Valve is Damaged or Stuck Closed

Canister Vent Valve

If the canister vent valve is stuck closed, it can also cause a P1450 code. The vent valve is responsible for providing an opening for the ambient air to suck in and carry the fuel vapors with it to the engine air intake manifold.

If the vent valve is closed, no air will enter the EVAP system. As a result, there will be an excessive vacuum in the EVAP system.

How to diagnose?

The canister vent valve is under the vehicle near the fuel tank.

If there is no damage to the wiring harness of the vent valve, remove the vent valve from the vehicle and apply a direct current to the vent valve to see if it functions or not i.e. closes from the opened state or opens from the closed state.

I found the below video really helpful to test the vent valve and the wiring harness plugged into it. You should watch it till the end.

Another way to diagnose a canister vent valve is to connect it with the vacuum pump just as we do to test the EVAP purge valve.

But for the canister vent valve, if the vacuum pump is not showing any vacuum, it means that the vent valve is healthy. If the pressure developed in the vent valve and it is being shown on the vacuum pump, it means that the vent valve is stuck closed.

Note: A vent valve holds a vacuum when it is opened.

4. Blocked or Damaged Charcoal Canister

If there is no dirt or debris in the vent valve tube and the vent valve is also working fine based upon the test performed above, chances are that the charcoal canister is blocked, which is causing P1450 code.

Find the charcoal canister under your Ford vehicle. Remove it, and check it for signs of damage caused by liquid fuel.

The interior of a charcoal canister is filled with carbon pellets. So, after taking out the charcoal canister, shake it and see if water, liquid fuel, or loose charcoal granules fall out. If yes, it means the charcoal canister is defective.

How to detect?

Another way of checking a blocked charcoal canister is to connect a new rubber vacuum hose to the port of the canister that is linked with the vent valve.

Blow through the other end of a vacuum hose and see if you feel any resistance. If yes, it means the canister is blocked and needs to be replaced.

Make sure that you do not inhale through the vacuum hose. Otherwise, the trapped fuel vapors could enter your lungs.

5. Damaged Fuel Filler Cap

Damaged Fuel Filler Cap

A fuel filler cap prevents escaping of fuel vapors after the fuel tank is filled. There is a relief function in the fuel filler cap that protects the fuel tank from venting when excessive fuel vapors pressure is present as well as allows atmospheric air to enter the fuel tank, thus providing a vacuum relief when the excessive vacuum is produced in the fuel tank.

fuel filler cap schematic
Illustration courtesy: Stant

However, after 2006, Ford stopped adding fuel filler caps in their vehicles. The Ford vehicles after 2006 have a capless fuel filler neck having a spring-loaded flap so that it is closed automatically as soon as the fuel nozzle is removed.

For the capless neck, check any dirt particles or debris in the sealing area around the inlet. One way of cleaning the debris around the filler neck is to jam the funnel into the capless filler neck and spray WD-40 or blow compressed air.

6. Defective FTP Sensor

Sometimes a defective fuel tank pressure sensor can also cause P1450 trouble and turns on the check engine light if it sends wrong signals of pressure in fuel tank to the ECM.

In most cases, the FTP sensor is mounted on the top of the fuel tank. In some vehicles, the FTP sensor is located inside the fuel tank.

How to test?

First, check the connector to the FTP sensor. Disconnect the connector. Turn on the ignition. You should get 5 or so volts from the 5v gray wire to the ground (black wire) on a multimeter.

With the ignition on and the connector still disconnected from the FTP sensor, you should get a sound from the green signal wire to the black ground or good body ground. 

If the wiring harness is fine, it’s time to test the FTP sensor. Turn ignition on. Connect the multimeter to the wire harness.

Apply a small vacuum to the outlet port of the FTP sensor using a vacuum pump. If the voltage on the multimeter decreases while applying vacuum, it means the FTP sensor is fine.

Final Thoughts

So, that’s all about all possible causes of the P1450 code in Ford vehicles. To cut into short, you should perform the following steps to troubleshoot P1450 in your Ford vehicle:

  • First, check all vacuum hoses and tubes in the EVAP system. Check for any cracks, debris, and bends.
  • If everything is fine, it’s time to check the EVAP purge valve which is the most likely cause of the P1450 code.
  • If the EVAP purge valve is fine, you should check the canister vent valve. Also, check any blockage in the hose connected to the vent valve.
  • If the vent valve is fine, check whether the charcoal canister is blocked.
  • Also, check the debris and dirt around the opening of a fuel filler neck.
  • Lastly, check the FTP sensor.

I hope you would have found this guide helpful. To troubleshoot each component of the EVAP system, you should have a vacuum pump and a good quality multimeter, and some tools to remove the EVAP components. Also, consult your owner’s manual to find the correct way of removing any EVAP component.

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