2012 Dodge Avenger P0441, P0455, and P0456 Evap System Issues - Check Engine Light Persistent After Gas Cap Replacement
I recently replaced the evaporative (Evap) purge valve and had the Evap hoses and lines professionally inspected — no visible leaks were found. However, the check engine light remains on despite these efforts, with persistent codes P0441, P0-455, and P0456. Additionally, my gas cap warning indicator activated, so I replaced the gas cap; unfortunately, the indicator does not turn off. Given that these codes are linked to evaporative system leaks, what could be causing this? Is it possible the issue lies in a hidden leak or sensor malfunction? What steps should I take next — such as a professional smoke test or diagnostic scan with a capable tool? Any insights for 2012 Dodge Avenger owners facing similar issues would be greatly appreciated.
You're reporting only P0441, P0455, and P0456 — are there any other diagnostic codes or symptoms? How was the Evap system tested — visually or with a smoke test? A generic OBD2 scanner might miss certain fault conditions. Is your vehicle registered under federal or California emissions standards? This could influence TSB (Technical Service Bulletin) applicability. These codes typically indicate a significant evaporative leak. I recommend starting with a professional smoke test to detect hidden leaks. Additionally, use an advanced scan tool to monitor the purge valve operation — does it achieve proper vacuum during the purge cycle? What is the vacuum decay rate and how does the TPS (Throttle Position Sensor) respond? Don't overlook the ESIM switch or evaporative filter as potential contributing factors.