Audi S8 Warning Light Needs System Readiness Test

Had a similar situation with my 2012 Audi S6. The car diagnostics initially showed incomplete system readiness after the check engine light came on. This is actually quite normal after the battery gets disconnected or codes get cleared. To get accurate OBD readiness status, I had to complete specific drive cycles. The process took about 3 days of regular driving, mix of city and highway speeds, including cold starts in the morning. The exhaust system and emissions test components need time to run their self-checks. A trustworthy shop should explain that system readiness monitors need time to complete their cycles. They cant properly diagnose issues if the readiness checks havent finished. In my case, once all monitors were ready, the car diagnostics revealed a faulty oxygen sensor that was affecting the fuel mixture. Red flags to watch for: Shops rushing to make repairs before system readiness is complete, Not explaining why they need to wait for monitors to be ready, Pushing for expensive repairs without showing clear diagnostic evidence Best approach is waiting until all readiness monitors complete their cycles before getting a full diagnosis. This ensures accurate readings and prevents unnecessary repairs.

Thanks for sharing your experience. I had nearly identical readiness monitor issues with my S8 last winter. After the computer reset and completing the drive cycles, it turned out to be just a loose gas cap causing the system to flag a pressure leak. Pretty relieved it was something so minor. Curious how much the oxygen sensor replacement ended up costing you? Also wondering if youve had any similar issues pop up since getting it fixed? The readiness monitors on these Audis can be quite sensitive to even small issues in the exhaust system.

Good news to report back, since getting the oxygen sensor replaced, I havent experienced any more check engine lights or onboard diagnostics issues with my S6. The repair was fully covered under extended warranty, so it cost 0 Euro. Most importantly, the system readiness check has remained complete after the fix. The mechanic confirmed all monitoring systems are now working as intended through OBD2 testing. These Audi engines are quite particular about their sensor readings, especially anything connected to the exhaust system. Glad your situation turned out to be just a loose gas cap. A proper drive cycle often helps reveal whether issues are serious or minor. The key is having a shop that takes the time to let all diagnostic monitors complete their checks before making repair recommendations.

After calling multiple shops, I finally found a mechanic who properly explained the drive cycle requirements. He advised waiting for all system readiness monitors to complete before doing any repairs. The whole process took about 4 days of normal driving to get accurate car diagnostics. The vehicle inspection ended up being straightforward once the computer reset had time to finish its cycles. They found a small vacuum leak near the intake manifold costing 350 Euro to fix. The mechanic showed me clear diagnostic data proving the issue rather than just telling me to trust their word. Having dealt with mechanics who tried rushing repairs before, I really appreciated how this shop handled everything. They took time explaining the emissions test results and what specific drive cycles were needed. No pressure to do unnecessary work. Will definitely use them again if any future check engine lights pop up. Looking back, its important to find a repair shop that understands these modern engine management systems. The right diagnostic approach makes a huge difference in getting problems fixed correctly the first time.