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DTC codes / Ford codes / P1457

P1457 · FordUnable To Pull Vacuum In Tank

P1457 on Ford vehicles means the powertrain control module (PCM) commanded the evaporative emission (EVAP) system to pull a vacuum on the fuel tank and did not see the expected pressure drop within the test window. The PCM monitors the fuel tank pressure sensor during a key-off or running vacuum test and flags this code when tank pressure fails to fall below the calibrated threshold.

SystemPowertrain
Code typeFord specific
SeverityMedium
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Often no symptoms besides the warning light, because the fault is a small leak or a blocked path that does not affect driveability.
  • A faint fuel odor around the rear of the vehicle or near the fuel filler neck after parking.
  • Fuel cap that feels loose, clicks weakly, or is visibly damaged or missing its seal.
  • Rough idle or a slight stumble on some vehicles if a stuck-open purge valve is feeding fuel vapor into the intake.
  • Failed state emissions inspection because the EVAP monitor will not complete.
  • Intermittent code that returns after a few drive cycles, especially after refueling.

Common causes, most likely first

  1. Faulty or loose fuel filler cap, including a missing, hardened, or incorrectly seated gasket.
  2. Cracked or disconnected EVAP hose between the fuel tank, canister, and purge valve, often at a plastic connector or a rub point.
  3. Stuck-closed or restricted EVAP canister purge valve that cannot open to draw vacuum on the tank.
  4. Leaking or saturated EVAP charcoal canister, sometimes from overfilling the fuel tank.
  5. Faulty fuel tank pressure sensor giving a false reading so the PCM never sees vacuum build.
  6. Blocked EVAP vent solenoid or vent line that prevents the system from sealing and pulling vacuum.
  7. Small leak at the fuel tank seal, filler neck, or a rusted EVAP hard line on older Ford trucks and SUVs.

How to diagnose and fix it

  1. Inspect the fuel filler cap first: check the gasket for cracks or hardening, clean the sealing surface, and reinstall it until it clicks; clear the code and run the EVAP monitor.
  2. Visually trace every EVAP hose from the tank to the canister and purge valve, looking for cracks, disconnected fittings, and rub-throughs, and repair or replace as needed.
  3. Command the purge valve open and closed with a scan tool and listen for a click; if it does not respond or is stuck closed, test its coil resistance and replace it if out of specification.
  4. Check the EVAP vent solenoid for proper operation and confirm the vent line is not plugged by debris or a spider nest.
  5. Compare the fuel tank pressure sensor reading to actual conditions with the key on and during a commanded vacuum test; replace the sensor if the reading is erratic or does not change.
  6. Perform a smoke test on the EVAP system to pinpoint small leaks at the tank, filler neck, canister, and lines that visual inspection missed.
  7. After repairs, clear the codes and complete a full EVAP monitor drive cycle to confirm the code does not return.

What Ford EVAP tests really check

  • A P1457 can be set by a fuel cap that was simply left loose after refueling, so always check the cap and its gasket before replacing any EVAP component.
  • On many Ford vehicles the EVAP monitor only runs after a cold start with the fuel level between about 15 and 85 percent, so a code that appears only after refueling points to a tank or filler neck issue.
  • A stuck-closed purge valve can cause this code and also produce a rough idle or a fuel smell, so do not assume the fault is always a leak at the rear of the vehicle.
  • Overfilling the fuel tank can saturate the charcoal canister and create a restriction that prevents vacuum from forming, which is a common missed cause on high-mileage Fords.
  • The fuel tank pressure sensor is often replaced unnecessarily; verify its reading against a known-good vacuum source before condemning it.

Can I keep driving with P1457?

You can usually keep driving with P1457 because it does not affect engine performance, but avoid topping off the fuel tank and get the EVAP system checked soon so the fault does not worsen or fail an emissions test.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage