Audi S5 Engine Stalls: EVAP System Issues Explained

Had similar symptoms with my 2011 Audi S4 last summer. The check engine light and stalling pointed to an EVAP system failure. The activated charcoal filter was completely clogged, causing pressure buildup in the fuel tank. This prevented proper fuel tank ventilation and created vacuum issues. A leak detection test revealed the EVAP system wasnt maintaining proper pressure. The emission control system kept switching to limp mode, triggering the check engine light. The pressure sensor readings were way off normal parameters. The fix required: Complete replacement of the charcoal canister, New purge valve installation, System pressure test, Computer reset to clear codes This was a significant repair that needed immediate attention since it affects emissions and fuel system operation. Left unfixed, it can lead to further fuel delivery problems and increased emissions. Tell your mechanic to: 1. Run a smoke test on the EVAP system 2. Check purge valve operation 3. Test the pressure sensor readings 4. Inspect the charcoal canister for saturation A proper diagnosis needs specialized equipment to test the EVAP system thoroughly. Unusual stalling and check engine lights are classic symptoms of this issue in these models.

Thanks for sharing your experience. I dealt with almost the exact same issues on my Audi S5 a few months ago. The pressure sensor readings were completely off and the check engine light kept haunting me. After replacing the charcoal canister and purge valve the fuel efficiency improved significantly and all issues were resolved. How much did your repair end up costing? Have you experienced any similar EVAP system problems since the fix was completed?

The complete repair solved all my EVAP system problems. The defective activated charcoal filter replacement came to 275 Euro, which was reasonable considering the improved fuel efficiency and resolved emission control issues. Since fixing the fuel tank ventilation system leak, the check engine light has stayed off and the pressure readings remain stable. The repair completely eliminated the stalling problem and restored proper EVAP system operation. No issues have returned in the months following the fix. The investment was worth it since poor fuel tank ventilation can lead to more expensive problems if left unchecked. The repair shop did a thorough job testing the system after installation to ensure everything was working correctly.

My search for a reliable fix finally ended last week. After getting recommendations from this forum, I went to a specialized import shop that actually knew what they were doing. The total repair came to 320 Euro, which included: The mechanic confirmed the air flow issues were caused by a failing purge valve, exactly as suggested here. They showed me the clogged charcoal filter and demonstrated how it was affecting the emission control system. The diagnostic equipment they used picked up multiple EVAP system faults that my previous mechanic missed completely. After replacing the components, they ran a full system check to ensure proper fuel tank pressure. The car runs perfectly now, no more stalling, no check engine light, and fuel economy has improved noticeably. Really glad I found this forum and got proper guidance on what to have checked. Would have saved time and money if I had known this from the start.