P0448

EVAP System Vent Control Circuit Shorted

Car Fault Codes Emissions & exhaust

Can you still drive? Yes, normally

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 2 hours

Typical cost SAR 100 to 700

What it means

The engine computer has detected a short in the vent valve circuit, to ground, to a voltage source or inside the valve coil. The valve may stay closed all the time, so pressure or vacuum builds in the tank and refueling becomes difficult.

Symptoms4

Check engine light on.
Difficult refueling with the nozzle clicking off early if the valve stays closed.
Occasional strong rush of air when opening the fuel cap.
Usually no driving symptoms.

Possible causes5

Internal short in the vent valve coil.
Control wire chafed under the vehicle and shorted to ground.
Water inside the connector.
Control wire shorted to a nearby power wire.
Faulty driver circuit inside the engine computer (rare).

How to diagnose5

Measure the valve coil resistance; a very low reading means an internal short.
Unplug the valve and see whether the code changes, which points to the valve itself.
Check the control wire for a short to ground or to voltage.
Check the connector for moisture or corrosion.
Watch tank pressure on a scan tool to confirm the valve is not stuck closed.

How to fix5

Dry and clean the connector or replace it.
Repair the shorted wire and protect it from chafing.
Replace the vent valve if its coil is shorted.
Have the computer circuit checked if the fault returns after repairing the valve and wiring.
Clear the codes and confirm the valve works with a scan tool.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low when a wire or connector is to blame, and rises when the vent valve near the tank is replaced.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Why do I hear a rush of air when opening the fuel cap?

A vent valve stuck closed stops air entering the tank, so vacuum builds inside and is released as a rush of air when the cap is opened.

What is the difference between P0447 and P0448?

P0447 means the vent valve circuit is open. P0448 means there is a short in the circuit or inside the valve coil.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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