Evaporative System Large Leak Detected
What it means
The computer could not build the expected vacuum in the evaporative system, meaning there is a large opening or a disconnected line. The most common cause is a fuel cap that was left off or not tightened after refueling.
Symptoms3
- Check engine light, often right after refueling.
- Noticeable fuel smell around the car.
- Usually no effect on driving.
Possible causes5
- Missing or loose fuel cap.
- Disconnected or cut evaporative hose.
- Purge valve stuck open or vent valve stuck.
- Broken charcoal canister.
- Damaged fuel filler neck.
How to diagnose and fix5
- Make sure the fuel cap is present and tightened until it clicks.
- Clear the code and watch whether it returns.
- Inspect hoses around the tank and canister for a disconnected line.
- Test the purge and vent valves.
- Request a smoke test if the cause is not obvious.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
If the cap is to blame the cost is minimal, reaching the second tier if the canister or its valves need replacing.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Frequently asked questions
I left the fuel cap off. Is putting it back enough?
Usually yes. Tighten the cap and clear the code, or wait for the light to go out after a few days of driving.
Is the fuel smell dangerous?
Fuel vapor is flammable. If the smell is strong, do not smoke near the car or leave it in an enclosed space, and have it checked promptly.
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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