Buick Regal GS Check Engine: System Readiness Alert

I had a similar situation with my 2016 Buick LaCrosse last month. I have some experience working on cars, mainly basic maintenance and troubleshooting. The check engine light appeared right after I had the onboard diagnostics system scanned. This is actually quite common after OBD2 readings, as the vehicle computer needs to complete a new drive cycle to reset all system readiness monitors. The solution was completely free, I just needed to follow a specific drive cycle procedure: Start with a warm engine, Drive at steady highway speeds for 15 minutes, Include several starts and stops, Let the car idle for a few minutes After completing this cycle, the check engine light cleared itself and all system readiness monitors showed complete status when checked again. Before suggesting more specific solutions, could you share: Have you recently disconnected the battery? What specific readiness monitors are showing as incomplete? Are you using a basic code reader or a more advanced diagnostic tool? Has any recent work been done on the emissions system? This information would help determine if your situation requires more than just a basic drive cycle to resolve the vehicle inspection status.

Latest service was 2 weeks ago for regular maintenance at 63697 KM. After doing the drive cycle exactly as suggested, the onboard diagnostics system is still showing incomplete readiness. The battery was never disconnected and no emissions work was done recently. I am using a standard OBD2 reader that shows 3 monitors are incomplete. The check engine light remains on despite multiple drive cycles. Given these unresolved system readiness issues, I am concerned there might be a deeper problem with the emissions control components.

Based on your update, I can share my similar experience with the Buick LaCrosse. When my car diagnostics showed persistent incomplete readiness monitors even after multiple drive cycles, it turned out to be more than just a reset issue. The recurring incomplete monitors were actually pointing to a failing oxygen sensor in my exhaust system. A standard OBD2 reader often doesnt show the full picture. When I had it properly diagnosed with an advanced scanner, it revealed the sensor wasnt properly communicating with the computer system. Since your symptoms match what I encountered and the check engine light persists, you might want to: 1. Have the emissions test done with a professional grade scanner to identify which specific monitors are incomplete 2. Check the oxygen sensor signals and exhaust system components 3. Get a computer reset performed by a shop with proper diagnostic equipment In my case, replacing the faulty O2 sensor resolved the readiness issues. The repair took about an hour, and after that, all monitors completed their cycles normally. This is fairly common on these models when they reach around 60-70k kilometers. Would suggest having a professional check the sensor values before replacing any parts, as this will confirm whether your situation matches what I experienced.

Thanks for the detailed follow-up about the O2 sensor issue. My situation definitely seems similar, dealing with these persistent OBD readiness problems even after following the drive cycle steps. Going to schedule an appointment to have the exhaust system and sensors professionally checked since multiple drive cycles haven't resolved it. The car diagnostics need to be reliable before my upcoming emissions test, so getting proper verification of the oxygen sensor values makes sense. Will report back after the professional scan reveals which specific components are causing these incomplete monitors to stay active.