P0448 code meaning
EVAP System Vent Control Circuit Shorted
Powertrain system Generic code P04xx codes Check engine light
What P0448 means
The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. P0448 is the short-circuit code of the older scheme for the vent valve. Subaru (also in the Saab 9-2X) expects supply voltage above 10 V at the module output with the valve off; a short to positive or a coil below 1 Ω sets the code after two drives, and Subaru then also replaces the module, as its driver may be damaged. Nissan and Infiniti use P0448 differently, for a vent valve or vent path stuck closed by dust or water, with replacement of canister, valve and filler tube. GM and Ford do not use the code.
P0448 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P0448
- Check engine light on
- Refuelling problems if the vent is blocked
- EVAP leak test does not run
Common causes of P0448
- Most likelyVent valve or vent path blocked by dust, dirt or water (Nissan reading)
- PossibleVent valve coil shorted (below 1 Ω)
- PossibleControl wire shorted to positive
- Less likelyModule driver damaged
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EVAP vent valveVent valve wiringCharcoal canisterEngine control module
What each part of P0448 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 48 | The exact fault in that area. |
What to do next
- Note P0448 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0448
What does P0448 mean?
P0448 means "EVAP System Vent Control Circuit Shorted". The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. It is a generic code, so it means the same on every make.
Is it safe to drive with P0448?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0448 fail an emissions test?
Yes, it can. P0448 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0448 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0448 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.