P0448: How to Diagnose & Fix — Evaporative Emission Control System Vent Valve/Solenoid Circuit Open
3 vehicles · 2 makes · $60-$900 repair
How to diagnose and fix P0448: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Focus · 2012–2018
The 2012-2018 Ford Focus with the 2.0L GDI engine experiences frequent canister purge valve (CPV) failures that cause rough idle, stalling, difficulty starting (especially after refueling), and fuel-related DTCs. The purge valve sticks open, allowing fuel vapors to flood the intake manifold at inappropriate times. This is separate from the carbon buildup issue and is one of the most commonly replaced components on the 2012-2018 Focus. Ford issued TSBs addressing the issue and released updated purge valve designs. The problem affects both manual and automatic (PowerShift) transmission models. Focus Fanatics Forum documents this as one of the top five most-replaced parts on the Mk3 Focus.
Common Symptoms
- Rough idle or engine surging at idle
- Engine stalling after starting, especially after refueling
- Difficulty starting the engine (extended crank time)
- Check engine light with EVAP system codes
- Fuel smell from engine bay
- Hesitation during acceleration from a stop
- Engine runs rich (black exhaust smoke)
How to Fix
Replace the canister purge valve (Motorcraft CX-2571 or equivalent, $30-60 part). The valve is located on top of the engine near the intake manifold and is a 15-30 minute DIY job. Use the updated Ford part number to avoid repeat failures. Clear all stored codes after replacement and drive through one complete drive cycle to verify the fix. If codes P0452/P0453 persist after purge valve replacement, the fuel tank pressure sensor may also need replacement.
Sources for this issue (1)
Nissan Altima · 2007–2020
After a loose/failed gas cap, the most common cause of EVAP leak codes (P0455 large leak, P0456 very small leak) on the Altima is a failed EVAP canister vent control valve mounted near the charcoal canister at the rear of the vehicle. The valve seal sticks or fails to seal, so the EVAP system can't pass its self-test. It typically starts as an intermittent small leak (P0456) and worsens into a gross leak (P0455). It does not affect drivability but causes a persistent check engine light and an emissions-test failure. Nissan issued TSBs (NTB09-020F, NTB13-097J, NTB17-082a) addressing the diagnostic path and this component.
Common Symptoms
- Check engine light with no drivability change
- Failed state emissions / smog test
- Fuel odor in some cases
- Code returns after replacing only the gas cap
How to Fix
Begin with a known-good OEM gas cap (aftermarket caps often will not seal). If the code persists, smoke-test the EVAP system; a sticking/leaking vent valve is the usual culprit and is replaced as a unit. OEM vent control valve part numbers for this generation include 14935-JF00E / 14935-JF01C / 14935-JF02C (supersession family 14935-JF00A through JF02C). Valve runs roughly $60-$110; OEM gas cap $25-$40.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Nissan fuel-filler cap 17251-ZX60A
2007-2012 Nissan Altima for this card, within the page's broader 2003-2012 fitment; verify VIN and filler-neck application.
- Genuine Nissan fuel-filler cap 17251-9BD0F
2013-2018 Nissan Altima; verify VIN/current supersession and cap-seal failure before purchase.
- Genuine Nissan fuel-filler cap 17251-5RL0B
2019-2020 Nissan Altima for this card, within the page's broader 2019-2025 fitment; confirm VIN and filler-neck application.
- Genuine Nissan EVAP canister vent-control valve 14935-JF02C
2009-2020 Nissan Altima for this card, within the page's broader fitment; verify VIN/current supersession.
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Sources for this issue (3)
Nissan Rogue · 2008–2013
Rogue owners commonly report EVAP system faults caused by a sticking vent control valve, contaminated canister, or related hose issues. The problem often shows up as a persistent check engine light and, in some cases, the gas pump repeatedly clicks off during refueling because the tank cannot vent properly. Nissan service literature for EVAP leak and vent valve diagnosis exists, and complaint/forum activity is consistent across this generation.
Common Symptoms
- Check engine light on
- Gas pump shuts off repeatedly while refueling
- Small or large EVAP leak codes
- Fuel odor near rear of vehicle
- Failed emissions inspection
How to Fix
Diagnosis includes smoke-testing the EVAP system, checking vent valve operation, inspecting the canister for saturation or debris, and verifying hose integrity near the rear of the vehicle. Repair may involve replacing the EVAP vent control valve, charcoal canister, damaged hoses, or corroded connectors, then clearing codes and confirming monitor completion.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Nissan EVAP canister vent-control valve 14935-JF02C
Not the engine-bay purge valve. The 2008-2010 drain-cut 14935-AM60B branch is excluded because its inspected OE listing was unavailable; confirm VIN and production date.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipIf replacing the vent valve, inspect the canister and nearby hoses at the same time because debris or saturation can cause repeat failures.
Find P0448 by make
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P0448 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0448 mean?
P0448 stands for "Evaporative Emission Control System Vent Valve/Solenoid Circuit Open." This emissions code indicates the EVAP (evaporative emission) system's vent valve/solenoid circuit is reading as electrically open. The vent valve controls how fresh air enters the charcoal canister and is part of how the system seals itself to test for fuel-vapor leaks. When the computer commands the vent solenoid but its circuit stays open (no continuity), this code sets — it's an electrical fault in the valve or its wiring, not a fuel or driveability problem. You typically won't feel any difference in how the car runs, but it will fail an emissions test and may not seal for leak checks.
What are the most common causes of P0448?
The most common causes of P0448 are: Failed EVAP vent valve/solenoid (open winding), Open or broken wiring in the vent solenoid circuit, Corroded or disconnected vent valve connector, Poor power or ground feed to the solenoid, Damaged harness near the canister (often under the vehicle), Blown fuse supplying the EVAP solenoid, Faulty ECM/PCM driver circuit. The specific cause varies by vehicle.
How much does it cost to fix P0448?
Repair costs for P0448 range from $60 to $900, depending on the vehicle and root cause.
Which vehicles are affected by P0448?
Au7o has documented P0448 across 3 vehicle models from 2 manufacturers: Ford, Nissan.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.