S7 Speedometer Error Linked to Failed OBD Readiness Test

Had a similar situation with my Audi S5 2015. The onboard diagnostics showed incomplete readiness monitors after a computer reset. This is actually common when the battery has been disconnected or after certain repairs. To resolve the system readiness status, you need to complete a proper drive cycle. This typically involves: Starting with a cold engine, Driving at steady highway speeds for 15-20 minutes, Including some city driving with stops and starts, Running the engine through various load conditions The check engine light and speedometer issues are often connected to the vehicle systems not completing their self-tests. In my case, it took about 3 days of normal driving before all monitors were ready. The good news is this usually isnt a serious mechanical problem, but rather an electronic monitoring issue. However, you are correct that failing system readiness can cause inspection failures since the onboard diagnostics need to be fully operational for emissions testing. Recommend having a professional scan tool check which specific monitors are incomplete before investing in major repairs. Sometimes its just a matter of driving the vehicle normally to allow the computer to complete its testing sequence.

Thanks for sharing your experience. The drive cycle steps helped me fix my readiness monitors too. The speedometer eventually started working correctly after a few days of driving, exactly like you mentioned. Did you remember how much the diagnostic scan cost you at the shop? Also wondering if youve had any similar electronic glitches since then? My onboard diagnostics seem fine now but want to make sure I can catch any early warning signs if this happens again before my next vehicle inspection.

Good to hear you got it sorted out just like I did. After taking my S5 to the mechanic, they ran the onboard diagnostics check for free, so there was no cost involved. The system readiness status is now complete and hasnt shown any issues since then. One tip for catching early warning signs, regularly check if your vehicle inspection monitors are ready through a basic OBD2 scanner. These affordable tools can help monitor system readiness between regular service intervals. What helped in my case was following the drive cycle pattern consistently whenever any electronic glitches appeared. The speedometer issue never came back after the initial fix. Just keep in mind that if you ever disconnect the battery or get major computer-related repairs, you might need to repeat the drive cycle to reset all emissions test parameters. Its quite normal for modern vehicles to need this electronic recalibration occasionally.

Thanks everyone for the help. Finally went to a new mechanic today who properly diagnosed everything. The diagnostic scan was 85 Euro and they found that my exhaust system sensors needed recalibration after a recent battery replacement. Did exactly what was suggested, followed a proper drive cycle for 3 days. Drove normally on highways and city streets, letting the car computer complete all its readiness tests. The speedometer is now working perfectly and all system monitors are showing ready status. The mechanic mentioned these electronic quirks are pretty normal after battery work or system resets. At least now I know what to watch for and wont panic if I need to do another drive cycle in the future. Car diagnostics can be frustrating but having it sorted before the inspection is a huge relief.