P1450 Fuel tank vacuum not bleeding off (Ford, Lincoln, Mazda)

Unable to bleed up fuel tank vacuum

Monitor

Most Ford and Mazda bulletins for P1450 describe only a check engine light, a slow fill or an inaccurate fuel gauge, so you can usually keep driving while you book a check.

It gets more serious if:

  • Inspect soon: Get it checked soon if the engine is hard to start, will not start, runs rough or loses speed after refuelling. Ford found this with P1450 on some 2013–2014 Escape, Fusion and MKZ, and a purge valve stuck open on the 2012–2018 Focus 2.0L was recalled because tank vacuum could cause stalling.

Source: how we rate severity

P1450 in short

On Ford, Lincoln and Mazda vehicles, P1450 means the engine computer could not bleed off vacuum in the fuel tank. A purge valve that sticks or leaks is the most common cause, with vent line blockages and software also named in bulletins. It is usually safe to drive, but get it checked soon if starting gets hard after refuelling.

The evaporative emissions (EVAP) system stores fuel vapour in a charcoal canister, and the engine draws that vapour in through a purge valve. During its self-test the computer seals the system and pulls a vacuum. Afterwards the vent should open and let the tank come back to normal pressure. P1450 sets when the tank pressure reading stays in vacuum.

On Ford and Lincoln this usually means air cannot get back in or the purge side keeps pulling. Ford bulletins name a purge valve that sticks or does not seal, a kinked fresh-air vent line, a blocked canister vent hose, and engine computer software on the 2015–2016 Focus 1.0L EcoBoost. Mazda traced it to the purge valve on the 2009–2013 Mazda6.

Too much tank vacuum can show up beyond the warning light. Ford bulletins mention slow filling at the pump, an inaccurate fuel gauge and, on some 2013–2014 Escape, Fusion and MKZ, hard starting or stalling after refuelling.

P1450 is a manufacturer code. We have only verified the meaning for Ford, Lincoln and Mazda; on other makes, check the meaning in that maker's service information.

Pick your make

P1450 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

  1. Canister purge valve sticking open or not sealing

    Supported by vehicle data
    Why it ranks here
    Ford bulletins for the 2016–2017 Focus RS and the 2013–2017 C-Max, Fusion and MKZ hybrids, and Mazda's bulletin for the 2009–2013 Mazda6, all trace P1450 to the purge valve. That makes it the best-supported cause.
    What would change this
    Rises if the tank pressure reading goes into vacuum at idle with purge commanded off. Falls if the valve holds vacuum when tested and the vent side is clear.
    How to test the evap canister purge valve

  2. Kinked or blocked fresh-air vent line or canister vent hose

    Supported by vehicle data
    Why it ranks here
    Ford found a kinked fresh-air vent line on 2017–2021 Transit, an obstructed canister vent hose on the 1998 Windstar, and moulding flash restricting an EVAP elbow on the 1997 F-Series, all setting P1450.
    What would change this
    Rises if the vent line is visibly kinked or crushed, or air will not pass through it. Falls if the line is clear end to end.
    How to test the evap canister vent valve

  3. Engine computer software (some Ford models)

    Supported by vehicle data
    Why it ranks here
    Ford's fix for P1450 on 2015–2016 Focus 1.0L EcoBoost built on or before 10/19/2015 is a computer reprogram, and the hybrid bulletin pairs a software update with the new purge valve.
    What would change this
    Rises if the dealer finds a newer calibration for the VIN. Falls if the computer is already up to date.

  4. Liquid fuel in the canister or vapour lines (2017 Escape and MKC)

    Possible — needs testing
    Why it ranks here
    Ford's service message for the 2017 Escape and MKC tells technicians to check for liquid fuel in the purge valve, canister and vapour lines when the purge valve is replaced. Engineering was still investigating, so this needs testing.
    What would change this
    Rises if liquid fuel is found at the purge valve or canister. Falls if the vapour side is dry.
    How to test the evap charcoal canister

  5. Canister vent valve stuck closed

    Possible — needs testing
    Why it ranks here
    If the vent valve stays shut, nothing lets air back into the tank after the self-test. Ford's 1998 bulletin lists P1450 alongside the vent control code P0446, but no bulletin we found names the vent valve alone.
    What would change this
    Rises if the vacuum stays when the vent valve is commanded open with a scan tool. Falls if the vacuum bleeds away normally.
    How to test the evap canister vent valve

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all stored codes and freeze-frame data, and note whether the light came on after refuelling or with a slow-filling tank.

    Low riskTool: OBD-II scan tool

    • IfP0455, P0456, P0457 or P0496 are stored with P1450

      It meansFord bulletins list these together for purge valve and vent line faults.

      Go to step 2

    • IfP1450 is the only code

      It meansStart with the bulletins for your model.

      Go to step 2

  2. Ask a Ford, Lincoln or Mazda dealer to check the VIN for software updates and bulletins, and for recall 18V-735 on a 2012–2018 Focus 2.0L.

    Low riskTool: VIN lookup at a dealer

  3. With the engine off and cool, follow the fresh-air vent line from the canister and look for kinks, crushed sections or a blocked hose end.

    Use cautionTool: flashlight

    Warning:Support the vehicle on ramps or stands, never just a jack, and keep sparks and flames away from the fuel tank and lines.

  4. With a scan tool that can command EVAP valves, watch the fuel tank pressure reading at idle with purge off, then command the vent valve open and see whether the vacuum bleeds away. On 2013–2020 Ford hybrids, the dealer test needs the fuel door step from SSM 48301 to give correct results.

    Use cautionTool: scan tool with bidirectional controls

    Warning:Run the engine outdoors or with exhaust extraction, and keep hands and clothing clear of belts and the fan.

Symptoms

  • Check engine light on
  • Fuel pump nozzle clicks off early, slow to fill
  • Fuel gauge reads wrong
  • Hard start, no start, rough idle or loss of RPM after refuelling Gets more serious: stop and have it checked.

Compare with: Check engine light came on after getting gas

How to fix

  1. Ask a dealer to check the VIN for software updates and bulletins first. Several P1450 fixes are a reprogram or a part covered by a bulletin.

  2. On a 2017–2021 Ford Transit, ask about bulletin 21-2106. Ford's fix for the kinked vent line is a zip tie that holds it in shape.

  3. Note whether the light came on after refuelling and whether the tank is slow to fill. This helps the shop pick the right test.

Parts and cost context

  • EVAP canister purge valve:The most-named part in P1450 bulletins. On some Ford hybrids it is replaced together with a software update. Labour varies; get a quote.
  • EVAP canister vent valve:Check the vent line for kinks before replacing the valve; one Ford fix is just a zip tie. Labour varies; get a quote.
  • EVAP charcoal canister:Rarely the cause on its own. Check it for liquid fuel when the purge valve is replaced. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • 2012–2017 · Focus

    Supported by vehicle data

    Three different P1450 bulletins: a computer reprogram for the 2015–2016 1.0L EcoBoost, a sticking purge valve on the 2016–2017 Focus RS, and a fuel gauge concern on 2012–2014 models. 2012–2018 Focus 2.0L also had purge valve recall 18V-735. Bulletin status not verified.

    Related recall campaigns: 18V-735

  • 2017 · Mustang

    Supported by vehicle data

    2.3L built on or before 13-Jan-2017: bulletin for P0456, P1450 and P144C. Bulletin status not verified.

  • 2013–2017 · Escape

    Supported by vehicle data

    2013 models built on or before 11/9/2013 can be hard to start after refuelling with P1450; 2017 models may have liquid fuel in the EVAP vapour lines. Bulletin status not verified.

  • 2013–2020 · Fusion

    Supported by vehicle data

    2013–2014 cars can be hard to start after refuelling; hybrids and Energi get new purge valve plus software, and the dealer test needs the fuel door step. Bulletin status not verified.

  • 2013–2018 · C-Max

    Supported by vehicle data

    Hybrid and Energi: purge valve sealing fixed with new valve and software. Bulletin status not verified.

  • 2017–2021 · Transit

    Supported by vehicle data

    Built on or before 30-Nov-2020: a kinked fresh-air vent line causes slow filling and EVAP codes; the fix is a zip tie. Bulletin status not verified.

  • 16-0055Status unverified

    1.0L EcoBoost: MIL with DTC P1450, built on or before 10/19/2015

    2015–2016focus · issued · NHTSA 10075285

    Defines P1450 as unable to bleed up fuel tank vacuum and fixes it with a computer reprogram.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 17-0016Status unverified

    Focus RS 2.3L: MIL with P0456, P1450 and/or P144A

    2016–2017focus · issued · NHTSA 10095617

    Points to an intermittently sticking canister purge valve.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 17-0019Status unverified

    Mustang 2.3L: MIL with P0456, P1450 and/or P144C

    2017mustang · issued · NHTSA 10095621

    Service procedure for 2017 Mustang 2.3L built on or before 13-Jan-2017; the summary does not name the part.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 46525Status unverified

    MIL with P0455, P0456, P144C and/or P1450, rough idle or slow fill

    2017escape, mkc · issued · NHTSA 10109013

    When replacing the purge valve, check for liquid fuel in the vapour lines and canister.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 19-2207Status unverified

    Hybrid/Energi: MIL with P1450, P0456, P0457, P04EE and/or P04EF

    2013–2017c-max, fusion, mkz · issued · NHTSA 10162068

    Update computer software and replace the canister purge valve.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 48301Status unverified

    EVAP pinpoint test HX may give incorrect results

    2013–2020c-max, fusion, mkz · issued · NHTSA 10168790

    On hybrids, latch the fuel door and press the release before step HX22 so the dealer test reads correctly.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 16-0075Status unverified

    Hard start, no start or loss of RPM after refuelling

    2013–2014escape, fusion, mkz · issued · NHTSA 10183776

    Some cars built on or before 11/9/2013 also show P1450 and/or P0456.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 21-2106Status unverified

    Slow fill and/or MIL with EVAP codes

    2017–2021transit · issued · NHTSA 10191172

    Kinked fresh-air vent line; attach a zip tie to hold it open.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 15-0034Status unverified

    Incorrect fuel gauge with EVAP and catalyst codes

    2012–2014focus · issued · NHTSA 10057878

    Fuel gauge concern on the Focus with P1450 among the listed codes.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Lincoln

  • 2017 · MKC

    Supported by vehicle data

    Same service message as the 2017 Escape: check for liquid fuel when the purge valve is replaced. Bulletin status not verified.

  • 2013–2020 · MKZ

    Supported by vehicle data

    Shares the Fusion bulletins: refuelling hard start on 2013–2014, purge valve plus software on the hybrid. Bulletin status not verified.

  • SSM 46525Status unverified

    MIL with P0455, P0456, P144C and/or P1450, rough idle or slow fill

    2017escape, mkc · issued · NHTSA 10109013

    When replacing the purge valve, check for liquid fuel in the vapour lines and canister.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 19-2207Status unverified

    Hybrid/Energi: MIL with P1450, P0456, P0457, P04EE and/or P04EF

    2013–2017c-max, fusion, mkz · issued · NHTSA 10162068

    Update computer software and replace the canister purge valve.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 48301Status unverified

    EVAP pinpoint test HX may give incorrect results

    2013–2020c-max, fusion, mkz · issued · NHTSA 10168790

    On hybrids, latch the fuel door and press the release before step HX22 so the dealer test reads correctly.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 16-0075Status unverified

    Hard start, no start or loss of RPM after refuelling

    2013–2014escape, fusion, mkz · issued · NHTSA 10183776

    Some cars built on or before 11/9/2013 also show P1450 and/or P0456.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mazda

  • 01-012-14-2908AStatus unverified

    MIL with DTC P1450:00

    2009–2013mazda6 · issued · NHTSA 10098141

    Purge valve modified to stop P1450:00, unable to bleed up fuel tank vacuum.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0456EVAP system very small leak detected

    Shares causes Supported by vehicle data

    Ford bulletins list P0456 with P1450 for a purge valve that sticks or does not seal, and after refuelling problems on 2013–2014 Escape, Fusion and MKZ.

  • P0455EVAP system large leak detected

    Shares causes Supported by vehicle data

    Ford lists P0455 with P1450 on the 2017 Escape and MKC and the Transit vent line bulletin.

  • P0496EVAP purge flow when purge should be off

    Shares causes Supported by vehicle data

    Too much purge flow (P0496) and trapped tank vacuum (P1450) appear together in Ford's Transit and hybrid EVAP bulletins.

  • P0451Fuel tank pressure sensor reading out of its expected range

    Shares causes Supported by vehicle data

    On 2017–2021 Transit, a kinked vent line can set P0451 and P1450 together.

  • P0457EVAP leak detected from the fuel cap being loose or off

    Shares causes Supported by vehicle data

    Ford's 2013–2017 hybrid bulletin lists P0457 with P1450 for purge valve sealing.

All EVAP (evaporative emissions) codes

P1450 questions

Is it safe to drive with P1450?

Usually, if the car starts and runs normally. Get it checked soon if it is hard to start, stalls or runs rough after refuelling.

Why is my tank slow to fill with P1450?

Ford links slow filling to EVAP vent and purge problems, such as a kinked vent line on the 2017–2021 Transit or liquid fuel in the vapour lines on the 2017 Escape and MKC.

Does P1450 mean the same on every car?

No. It is a manufacturer code. We have verified the meaning only for Ford, Lincoln and Mazda. On other makes it may mean something different, so check that maker's service information.

Sources and review

  1. 1.0L EcoBoost: illuminated MIL with DTC P1450, built on or before 10/19/2015 (bulletin 16-0055) — Ford Motor Company / NHTSA ,
  2. Slow fill and/or MIL with EVAP codes (bulletin TSB 21-2106) — Ford Motor Company / NHTSA ,
  3. Incorrect fuel gauge indication with EVAP and catalyst codes (bulletin 15-0034) — Ford Motor Company / NHTSA ,
  4. Hard start, no start or loss of RPM after refuelling (bulletin 16-0075) — Ford Motor Company / NHTSA ,
  5. MIL with P0455, P0456, P144C and/or P1450, rough idle or slow fill (bulletin SSM 46525) — Ford Motor Company / NHTSA ,
  6. Part 573 Safety Recall Report 18V-735: canister purge valve (2012–2018 Ford Focus 2.0L) — Ford Motor Company / NHTSA ,
  7. MIL with DTCs P0456, P1450 and/or P144A (bulletin TSB 17-0016) — Ford Motor Company / NHTSA ,
  8. MIL with P1450, P0456, P0457, P04EE and/or P04EF (bulletin TSB 19-2207) — Ford Motor Company / NHTSA ,
  9. MIL with DTC P1450:00 (bulletin 01-012-14-2908A) — Mazda North American Operations / NHTSA ,
  10. MIL with DTC P1450, obstructed canister vent hose (bulletin 984989) — Ford Motor Company / NHTSA ,
  11. MIL with DTC P1450, restricted EVAP elbow (bulletin BC3230970211) — Ford Motor Company / NHTSA ,
  12. MIL with EVAP codes P1450, P0455, P0446 (bulletin 985103) — Ford Motor Company / NHTSA ,
  13. Final Regulation Order: 13 CCR §1968.2, Malfunction and Diagnostic System Requirements (OBD II), 2004 and subsequent model-year passenger cars, light-duty trucks and medium-duty vehicles (2015 amendments) — California Air Resources Board
  14. EVAP pinpoint test HX may give incorrect results (bulletin SSM 48301) — Ford Motor Company / NHTSA ,
  15. MIL with DTCs P0456, P1450 and/or P144C (bulletin TSB 17-0019) — Ford Motor Company / NHTSA ,
Last reviewed
Written by
Saurabh K.
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