P0455
Low severityEvaporative Emission System Leak (Large)
Quick answer
P0455 (Evaporative Emission System Leak (Large)) means: A large leak was detected in the fuel-vapor (EVAP) system — often a loose or faulty fuel cap. Low urgency; check the fuel cap first. Typical Malaysia repair cost: RM80–RM300 (approximate).
Symptoms
- •Check engine light
- •Possible fuel smell
Likely causes
- •Loose/faulty fuel cap
- •Cracked EVAP hose
- •Faulty purge/vent valve
Can I drive?
Low urgency; check the fuel cap first.
Estimated repair cost (Malaysia)
RM80–RM300 (approximate)
Diagnostic guide (for mechanics)
Work through these in order — cheapest and safest checks first, before replacing expensive parts.
1. Check the fuel cap first
A gross EVAP leak is most often a loose, missing, or failed cap. Re-seat and re-scan.
Test: Inspect/retighten cap; check seal.
Expected: Cap clicks and seals.
2. Inspect EVAP hoses and canister
Look for cracked or disconnected lines to the charcoal canister.
Test: Visual inspection of EVAP plumbing.
Expected: No cracks/disconnections.
3. Smoke-test the EVAP system
A large leak is readily found with EVAP smoke.
Test: EVAP smoke test.
Expected: No smoke escaping; locate any leak point.
Tools: OBD-II scan tool · EVAP smoke machine
When to escalate: Low safety urgency but it will keep the light on. Replace the failed cap, hose, or valve found by smoke test.
This is general information, not a diagnosis. AutoMalaya OBD helps explain your car’s actual scan data; a qualified mechanic may still need to inspect the vehicle.