Audi S3 OBD Readiness Issue Causing Inspection Concerns

As someone with some car repair experience, I had a very similar issue with my 2011 Audi RS3. The OBD readiness monitors showed incomplete status right after I had the battery disconnected for maintenance. No repair was actually needed in my case. The issue resolved itself after completing a proper drive cycle. The key is following a specific driving pattern to allow all system monitors to complete their tests. This typically involves: 1. Starting with a cold engine 2. Steady highway driving for 15-20 minutes 3. Some stop-and-go traffic 4. Idle time Most emissions test centers require all OBD monitors to show ready status before performing the vehicle inspection. This is completely normal after any work involving battery disconnection or ECU reset. The workshop confirmed through car diagnostics that nothing was actually wrong, the monitors just needed time to complete their self-tests. Cost was 0 Euro since it only required the diagnostic scan. To help further, could you share: Have you had any recent battery work or ECU resets? Which specific error message are you seeing? Are you able to read which monitors specifically show not ready?

Last service was at 159831 KM and the onboard diagnostics showed the exhaust system monitor was still pending. I followed the suggested drive cycle pattern but my computer reset didnt complete after 3 full days of normal driving. The OBD readiness status remains incomplete despite following all steps carefully. I did check with basic OBD scanner and found the catalyst efficiency below threshold code. Wondering if this indicates my catalytic converter might be failing rather than just being a drive cycle issue. Looking to get this resolved before my upcoming vehicle inspection. Would replacing the cat be the only solution or could cleaning help? The engine runs fine otherwise with no performance issues.

Thanks for those additional details about your S3. After seeing your catalyst code, this matches exactly what happened with my RS3 last year. While initially I thought it was just a drive cycle issue, it turned out my catalytic converter was actually starting to fail. The onboard diagnostics were correct in showing the catalyst efficiency code. When the check engine system cant complete the readiness test even after multiple proper drive cycles, its often because the cat converter isnt performing within specs anymore. In my case, I first tried a catalytic converter cleaner additive, but the OBD readiness monitors still wouldnt complete. Eventually had to replace the cat. After replacement: All system readiness monitors completed within one normal drive cycle, Check engine light cleared permanently, Exhaust readings returned to normal levels Cost for the replacement was around 900 Euro including labor. While not cheap, it solved the issue completely and passed inspection without problems. Would suggest having a workshop verify the catalyst readings with professional diagnostics before proceeding. They can check if the converter is actually degraded or if theres perhaps another underlying issue preventing the readiness monitors from completing.

Thanks for sharing the drive cycle experience. Makes sense now about the catalyst code showing up on the OBD scanner. My gut feeling was right that something more serious might be wrong with the exhaust system, rather than just being a readiness monitor issue. Will book the car in for proper onboard diagnostics to confirm if the catalytic converter really needs replacing. Given that normal driving isnt clearing the check engine status after multiple attempts, replacement seems likely. At least now I know what price range to expect if it comes to that. Good to hear replacing the cat solved similar issues completely. Better to sort this before the inspection than risk failing due to incomplete OBD readiness or emissions problems. Will update once I get the professional diagnosis results. Just hoping its actually the catalyst and not something else causing problems with the exhaust system monitoring. The car running fine otherwise gives me some peace of mind that its probably isolated to just the converter.