Home TroubleshootingOBD Codes P1450: What Does It Mean For Your Car?

P1450: What Does It Mean For Your Car?

by Kelvin Yates

Unlike many other DTCs, P1450 is a manufacturer-specific code that can only be displayed by specific vehicles like Mercedes, Jaguar, Ford, and a few more. Thus, the definition of this trouble code varies between models, however, the causes, symptoms, and repairs are similar regardless of the brand of the car.

P1450 is an extended error code of OBD-II code P1. Codes of this nature are written as P1XXX where the third number of the code sequence specifies where the issue is with the car’s OBD-II system. Here, the numeral 4 signified a problem with the auxiliary emission controls of the vehicle.

This control system detects vehicle speed, temperature, manifold vacuum, transmission gear, engine RPM, and so on. As it concerns DTC P1450, the Powertrain Control Module, or PCM of your vehicle has sensed a faulty fuel tank vacuum during engine operation.

This problem can be a pesky one, especially P1450 Ford Mustang and P1450 Ford Focus Recall. Stay tuned to find out how to approach this particular diagnostic trouble code.

What Does P1450 Code Stand For?

Manufacturer-defined OBD-II trouble code P1450 has two definitions – one from carmaker Ford and the other from the manufacturer’s Jaguar, Mercedes, Lincoln, Oldsmobile, and Mercury. Ford suggests that the code suggests that the engine can’t bleed fuel up into the vacuum (fun fact, go check out our guide on what happens if you accidentally put gas in your car while it’s running).

And the other brands defined it as the inability of the engine’s emission system for bleeding fuel into the tank. For those who do not understand mechanical jargon, the two terms mean the same thing.


Code P1450 is stored by the vehicle’s computer when the PCM senses an additional vacuum within the EVAP system and/or the fuel tank. “Bleeding” refers to the Powertrain Control Module’s incapacity to keep a particular vacuum condition in the EVAP system solely when the motor is operating at speeds over idling RPM.

Note: American automaker Ford also mentions a related DTC: P1452. This is very similar to P1450. The only noteworthy difference between the parameters of the code is that P1450 is set at engine speeds over idle whereas P1452 is stored during high-speed driving scenarios.

EVAP System

An EVAP system is tasked with capturing and containing fuel vapors right before they can be released into the environment. Fuel vapors find temporary storage in a charcoal canister in all EVAP units.

When a set of specific conditions are fulfilled, the PCM orders the purge valve to open, allowing the motor vacuum to remove the accumulated vapors from the charcoal canister and transfer it to the inlet tract using a dedicated vacuum line. This is then combusted as an element of the fuel-air blend.

To aid in the purging process, a vent valve is fitted into the EVAP system. The vent valve is generally open so when the process of purging is initiated, fresh air can enter the system and help remove fuel vapors from their storage – the charcoal canister. Amidst ongoing self-tests, the vent valve is closed by the PCM until a specified vacuum is created by the engine vacuum. How does this happen?

The fuel vapors are sucked out of the motor through the purge valve. Once the purge valve is closed, it seals the EVAP system. If the vacuum stays for a certain period, the PCM registers that there are no leaks, and the valve is opened once again, until another self-test.

In fully working EVAP systems, the vent valves stay open to effectively “clean” the EVAP system. Moreover, solely the purge valve, which generally stays closed, is ordered to open and close to purge fuel vapors. Thus, if the vent valve stayed closed for some reason it would block the vent valve or the charcoal canister. Air would not be able to enter the system, creating a vacuum exceeding the specific value upon opening the purge valve.

Therefore, DTC P1450 is stored, and a Check Engine Light is flashed across your vehicle’s dashboard. The vehicle is essentially unable to relieve the excessive vacuum. Keep in mind that particular conditions have to be fulfilled before this specific monitor can operate.

Valve’s Location

In these conditions, it is best to refer to the application’s manual. Note the vent valve’s location relative to other important components of the system. This valve has to be open to purge the EVAP system and provide air to the fuel system when refilling your vehicle. Refer to this video for more.

When the tank is filled, the charcoal canister absorbs the fuel vapors. After that, they are placed into the motor during the next purging cycle. Another big issue associated with a clogged or blocked vent valve is the increased difficulty in filling a tank. The incoming fuel cannot displace the air in the tank, making it difficult to refill a tank, if not impossible.

Codes Related to P1450

P1451 – “Evaporative emission control system vent control valve circuit fault”
P1453 – “Fuel tank pressure relief valve malfunction”
P1454 – “Evaporative system vacuum test malfunction”

Manufacturer Specific Definitions for DTC P1450

As mentioned earlier, not all brands of vehicles are plagued by this issue. Manufacturers set different definitions of P1450 in their cars.


Fault Location


Secondary air injection (AIR) system – short to positive
Toyota Fuel Tank Pressure Sensor
Suzuki Barometric pressure (BARO) sensor – circuit malfunction
Saab A/C relay – low output
Peugeot Unable To Bleed Up Fuel Tank Vacuum
Mini Diagnostic Module Tank Leakage Switching Solenoid Open Circuit
Mercury Evaporative emission (EVAP) system, vent control -circuit malfunction
Mazda Evaporative emission (EVAP) canister purge system – leak
Lincoln Evaporative emission (EVAP) system, vent control -circuit malfunction
Lexus Fuel tank pressure sensor- circuit malfunction
Land Rover Evaporative emission (EVAP) pressure pump – circuit plausibility
Kia Evaporative emission (EVAP) canister purge system – vacuum leak detected
Gm Barometric Pressure Sensor Circuit Conditions
Geo Barometric Pressure Sensor Circuit Fault
Ford Unable to Bleed Up Bleed Fuel Tank Vacuum
Citroen Unable To Bleed Up Fuel Tank Vacuum
Chevrolet Barometric pressure (BARO) sensor -voltage out of range
Cadillac Barometric Pressure Sensor Circuit
Buick Barometric Pressure Sensor Circuit
BMW Engine oil pressure – too high
Audi Secondary air injection (AIR) system – short to positive

Two Way Valve Bypass Valve Control Circuit Low Voltage

Reference: Trouble Codes

Causes Of P1450 Code

Numerous factors may be causing your car to display trouble code P1450; the most common ones include:

  • Fuel vapor is unable to reach the EVAP from the fuel tank due to a bad connecting hose
  • Obstruction of the vent solenoid or the evaporative emission (EVAP) canister
  • Faulty or defective fuel tank pressure sensor
  • Stuck fuel filter cap resulting in hindered vacuum relief
  • Corroded, shorted, or defective connectors and wiring
  • Bad charcoal canister due to fuel tank overfilling

Signs Of P1450 DTC

P1450 is a bit of a low-key code where you will see a few symptoms, unlike many other trouble codes where the dashboard of your vehicle will light up with many different symbols and colors. It is mentionable that this OBD-II error code does not pose a threat to the vehicle’s drivability but stores the trouble in its memory. Symptoms include:

  • An illuminated Check Engine Light
  • Delayed starting of the engine after filling the tank (happens only in rarer cases).

How Serious Is P1450?

In comparison to other error codes, P1450 is not a serious DTC as it does not mean any negative implications for the vehicle’s drivability. In addition, it will not cause further damage to the engine either. Nevertheless, we recommend you never leave any error code unattended.

How Easy Is It To Diagnose A P1450 Code?

Certified mechanics troubleshoot this DTC by beginning their examination at the vent solenoid or EVAP canister where they search for blockage. Afterward, the mechanic will inspect the hose between the fuel tank and the canister and check for symptoms of a collapsed or kinked hose blocking the passage.

Next, they will check to see if the fuel filler cap is shut. Lastly, they will have a look at the Fuel Tank Pressure Sensor. Learn how to replace the EVAP canister with this video here.

Diagnosing P1450

Important Considerations: Ford Taurus, Explorer, Mustang, Edge, Flex, MKX, MKX, and MKT cars between the model years 2012 to 2013 featuring a 3.5-liter Twin-independent Variable Cam Timing (TiVCT) (also 3.7L engines made between March 1, 2012, and July 31, 2012) might display P1450 error code repeatedly, even if the charcoal canister and vent valve are functioning perfectly.

Note that P1450 Ford Escape means that the purge valve has failed and caused the fuel to be pushed into the charcoal canister, making the charcoal charge disintegrate. Replacing the EVAP system purge valve can resolve the affected parts.

Note: Non-professional technicians should gain a little perspective on some of the later Ford Escape variants. Accessing the vent valve and charcoal canister to test and/or remove or replace might require complete or partial rear axle removal. Keeping this in mind, we highly suggest checking if the EVAP system still falls under the manufacturer’s warranty when error code P1450 pops up on a late Ford Escape model. The equipment needed to extract the axle is rarely available to the general public.

Step 1

Note all present fault codes in addition to available freeze frame data. You can use this information if you diagnose an intermittent failure later on. There might be other codes related to the EVAP system in a few cases, some of which could be due to code P1450 while the rest may have aided in the storage of DTC P1450.

Check out your vehicle’s manual for specific information on any extra codes that could be present. However, make sure to follow the manual directions to the tee if the manual suggests other codes must be resolved before fixing P1450. Failure to do this can lead to misdiagnosis as well as almost certain unwarranted replacement of components and parts.

Step 2

See the application’s manual to find all the components of the EVAP system, as well as the routing, location, color-coding, and function of all related hoses, fuel/vacuum lines, and wiring. Once you have found all the parts, perform an in-depth visual examination of every related connector, wiring, fuel line, and hose.

Inspect for visible shorted, damaged, corroded, or disconnected connectors and/or wiring as well as symptoms of pinched, kinked, misrouted, or damaged vacuum lines. Make necessary repairs, clear all codes, and perform at least 1 drive cycle before rescanning the whole system.

Step 3

If you cannot spot visible damage to the connectors, wiring, hoses, or vacuum lines detected, close the vent valve using the scanner command. The scanner will display the closed/opened condition of the valve. Therefore, if the scanner shows the vent valve to be working, there is likely a block in the line connecting the vent valve, the charcoal canister, its pre-filter, or it could be the vent itself.

If there is no visible damage to the connectors and/or wiring and the vent valve stops reacting to the control inputs from the scanner, check the manual for the right process to check the control circuit of the vent valves. You need to inspect for ground resistance, connectivity, and continuity. Contrast all acquired reading with what you find in the manual. Replace/repair the wiring as needed to make sure that all electrical measures are within the specifications of the manufacturer.

Note: Cars that spend an extended period in storage or are often driven through muddy roads are primarily susceptible to vent valve blockage. It can be the mud or insects living in the inlet of the vent valve causing this condition (it can help to know how to get roaches out of car).

Step 4

Refer to the application manual if a clog is suspected and find the right procedure to dissolve the block. Check for signs of insect infestation and mud. If possible, remove the blockage, but make sure to deliver a direct current to the vent valve to ensure that it shuts properly.

Once the direct current is taken away, the vent valve should reopen – verify this truly occurs by a vent blow. If you cannot blow through the vent valve or are finding it impossible to do so, the valve is faulty, and the probable reason behind the P1450 code. Change the valve in this case.

Note: A great way to check the vent valve is by applying a vacuum to an opening using a hand-held vacuum pump during the application of current to the solenoid. Unless the test equipment is faulty itself, the vacuum will steady for 60 seconds at the very minimum. Register the valve as defective if it does not and replace the application.

Step 5

If the valve and inlet are clear and can hold a vacuum for around 60 seconds, take out the charcoal canister as well as its pre-filter. Examine for damage done by liquid fuel. Shake the canister and check if liquid fuel, loose charcoal bits, or waterfall out of it. If yes, the canister is defective, and the likely answer to why your vehicle has a P1450 code stores. Only replacing the canister can fix this situation.

Also, make sure to replace or clean the pre-filter. These filters can easily get blocked to the extent that no air can move through them. As they are relatively cheap, replacing them is generally the best option.

Note: If no water, loose charcoal bits, or fuel leaks out of the canister, connect the vent valve side of the component to a part of the new vacuum hose. Blow through it with lung power only. You may experience a little initial resistance.

Warning: DO NOT suck air in this position as you will end up inhaling residual fuel vapor. You do not want that for your lungs.

Step 6

If the vent valve, its connecting line, and the charcoal canister are clean and obstruction-free, take out all vacuum hoses associated with the EVAP. Remove all the hoses between the fuel tank and the charcoal canister from the car, and blow them clean using strongly compressed air.

Alternatively, you can poke a long, pliable, and soft wire through the connecting hoses to make sure there is no blockage in the way. Maintain caution during this step to avoid poking holes in the vacuum line.

I still, doubt if the vacuum line is completely free of blockages or not? Replace the vacuum hoses.

Step 7

Ask yourself these questions:

  • Is the vent valve working and not blocked?
  • Is the charcoal canister and the pre-filter serviceable?
  • Are all the blocks in the vacuum lines gone? Is it operational?

If the answer to all three questions is yes, the repair/diagnostic steps mentioned to this point have fixed the concern. If the code persists, however, keep in mind that if everything is functional, the P1450 purge valve cannot be the reason behind this issue. Stuck-open valves are mostly shown by codes that are not P1450, so if a code like that is not present with P1450, the purge valves and their functionalities are not likely not responsible for the plight of your vehicle.

The code might reappear after some drive cycles. If that is the case, it is likely caused by an internal issue in the vent valve solenoid or an intermittent wiring problem. Understand that even if those intermittent issues are often rather complicated to diagnose and repair, in a few cases, it may be important to let the fault worsen before precise troubleshooting and repair can be performed.

Common Mistakes

Mechanics often fail to properly examine all the parts, hoses, connections, and wirings of the EVAP system, the fuel tank, and/or the charcoal canister.

Taking the example of Ford, in most cases, the P1450 Ford or P1450 Ford Fusion can be fixed by removing the blockage in the connecting hoses or cleaning the system. Do not jump to part replacement.

What Repair Can Fix P1450?

For cases like the P1450 Ford F150 and P1450 Focus, some notable repairs may help resolve the DTC. Luckily, they are all fairly straightforward. They include:

  • Removing obstructions in the hoses connecting to the EVAP system (Alternate: Replacing the hoses if the other solution does not work)
  • Replacing or repairing the fuel filler tube
  • Replacing the charcoal canister.

Cost Of Replacement Of Parts

The average cost of a Ford Focus purge valve replacement ranges from $145 to $174. In this, labor costs are assumed to take up to $70 to $89 and the parts cost between $74 and $85. Taxes and fees are not included in this range.

For fuel filler neck replacement, the average cost is about $200.

P1450 Error Code Facts

  1. P1450 is an OBD-II error code that identifies an issue with a vehicle’s auxiliary emission controls, specifically a malfunctioning fuel tank vacuum.
  2. The code is always displayed as P1XXX, with the third numeral identifying where the OBD-II system has encountered a problem.
  3. The P1450 DTC is triggered when the Powertrain Control Module detects an excessive vacuum in the fuel tank or Evaporative Emissions Control System (EVAP).
  4. The only symptom associated with this code is the illumination of the check engine light, as it does not result in a noticeable fuel odor.
  5. Common causes of a P1450 error code include a blocked EVAP canister or vent solenoid, a defective tank pressure sensor, a collapsed or kinked hose, or a fuel filler cap stuck closed.
  6. It is imperative to have the car checked immediately when the check engine light comes on due to the possibility of uncontrolled release of hydrocarbons into the atmosphere.
  7. A P1450 DTC doesn’t immediately cause mechanical problems or impede driveability, but it is still important to get a proper diagnosis by a qualified professional and perform any necessary repairs.
  8. Qualified mechanics diagnose this code by starting their inspection at the EVAP canister or vent solenoid, checking the hose between the canister and fuel tank, and inspecting the fuel filler cap and Fuel Tank Pressure Sensor.
  9. Repairing or replacing the fuel filler cap is the most common solution, but sometimes the mechanic may have to repair or replace damaged or unhooked lines in the EVAP system.
  10. It is not difficult to inspect a P1450 code, but it requires proper diagnosis by a qualified professional to prevent any damage.

Last Words

Out of the many DTC a vehicle may store, the P1450 is straightforward and complicated at the same time. Once you detect which component is contributing to the code it is easy to resolve. But finding the application is the hard part. Following the guide stated above, you can easily find the causes of the issue and troubleshoot it.

Frequently Asked Questions (FAQs)

Here are some popular FAQs:

How Do I Fix Code P1450

Removing the blocks in the charcoal canister and/or vent valve should resolve P1450.

What Does Code P1450 Mean

Code P1450 defines a situation termed “Unable To Bleed Up Fuel Tank Vacuum.”

Can I Still Drive With A P1450 Code

We suggest you get a full diagnosis done as soon as possible. No immediate mechanical issues are posed by DTC P1450 so you can still drive the vehicle. However, nothing can offset the importance of a proper diagnosis done by a certified professional.

What Does P1450 Ford Explorer Mean

This indicates the EVAP suspects excessive fuel tank vacuum once the engine is operational and not idling. An error signal is transmitted to the PCM which sets off the Check Engine Light on the dashboard.

Is It Okay To Drive With A Bad Purge Valve

Although you can still drive your vehicle with a faulty purge valve, this exposes the EVAP system to further damage. It can also negatively affect your entire car. The more you drive the car with a poor purge valve, the more extensive damage is done to other parts. The problem has to be resolved at some point.

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