{"id":44807,"date":"2026-06-24T11:45:20","date_gmt":"2026-06-24T11:45:20","guid":{"rendered":"https:\/\/fastestvpn.com\/blogs\/?p=44807"},"modified":"2026-06-24T13:48:00","modified_gmt":"2026-06-24T13:48:00","slug":"p0455-code","status":"publish","type":"post","link":"https:\/\/fastestvpn.com\/blogs\/p0455-code\/","title":{"rendered":"P0455 Code: EVAP System Large Leak Detected – Causes, Symptoms & Fixes","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

If your check engine light just came on and a scan tool showed you code P0455<\/strong>, don’t panic. This is one of the most common OBD-II codes, and in many cases, it’s triggered by something as simple as a loose gas cap. But sometimes it’s more serious. This guide will walk you through everything you need to know – what the code means, why it triggers, how to diagnose it, and how much it costs to fix.<\/p>\n

\"P0455<\/p>\n

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What Is the P0455 Code?<\/h2>\n

P0455 is an OBD-II diagnostic trouble code (DTC) that stands for “Evaporative Emission Control System Leak Detected (Gross Leak\/No Flow).”<\/strong><\/p>\n

Your car’s EVAP (Evaporative Emission Control) system<\/strong> is designed to capture fuel vapors from the fuel tank and prevent them from escaping into the atmosphere. The system is completely sealed, and the ECM (Engine Control Module) regularly tests it by pressurizing the system and checking whether it can hold vacuum.<\/p>\n

When the ECM detects that the system cannot maintain pressure<\/strong> – meaning there’s a large leak somewhere – it stores the P0455 code and turns on the check engine light.<\/p>\n

The key word here is “gross leak”<\/strong> – which in technical terms means a leak larger than 0.040 inches (roughly 1mm) in diameter. This is a bigger leak compared to P0442, which flags small leaks.<\/p>\n

P0455 vs. P0442 – What’s the Difference?<\/h2>\n

These two codes are often confused. Here’s a quick comparison:<\/p>\n

\n\n\n\n\n\n\n
Code<\/th>\nLeak Size<\/th>\nUrgency<\/th>\n<\/tr>\n<\/thead>\n
P0442<\/strong><\/td>\nSmall leak (< 0.020 inch)<\/td>\nModerate<\/td>\n<\/tr>\n
P0455<\/strong><\/td>\nLarge\/gross leak (> 0.040 inch)<\/td>\nHigher<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

P0455 should be addressed sooner because a larger leak means more fuel vapors escaping, greater fuel waste, and a higher chance of related codes triggering.<\/p>\n

Related EVAP Codes to Watch For<\/h2>\n

If you see P0455 alongside other codes, the combination can help you pinpoint the issue faster:<\/p>\n