2020 Mercedes-Benz GLC P0455: Large EVAP Leak Repair

Tracking P0455 on Your 2020 Mercedes-Benz GLC

P0455 on your 2020 GLC (X253) means a large EVAP leak. Your GLC 300 with the 2.0L turbo may still be under warranty. Gas cap is the first investigative step.

Symptoms

• Check engine light with P0455
• Fuel smell possible
• Gas cap worn
• Emissions test failure

Causes by Likelihood

1. Gas Cap Seal (Very High Likelihood): Degraded after 4+ years. $15–$35.
2. Leak Detection Pump (Medium Likelihood): Mercedes LDP wear. $280–$500 installed.
3. EVAP Purge Valve (Medium Likelihood): Sticking. $200–$400 installed.
4. Fuel Tank Vent Valve (Low-Medium Likelihood): Seal deterioration. $220–$420 installed.
5. Vapor Hose (Low Likelihood): Age cracking. $120–$280.

Diagnosis

New gas cap first. If P0455 persists, XENTRY diagnostics or a smoke test will locate the leak.

Warranty

Mercedes' 4yr/50k warranty may have expired. Federal emissions (8yr/80k) covers EVAP through 2028.

Safe to Drive?

Yes. P0455 doesn't affect the turbo engine, 4MATIC, or any features.

Frequently Asked Questions