SQ5 O2 Sensor Failure Causing High Fuel Consumption

Had the same issue on my 2015 Audi S4 with the gas engine. The check engine light came on due to a faulty sensor in the exhaust system. Vehicle emissions were off the charts and fuel consumption increased by about 30%. The diagnostic revealed a failed oxygen sensor heater element. This is a common problem that affects the exhaust system performance and engine efficiency. During sensor testing, they found corroded wiring connections near the O2 sensor, which made the repair more complex than just replacing the sensor. The repair involved: Complete sensor testing of the exhaust system, Replacing the oxygen sensor, Repairing damaged wiring harness, Clearing fault codes, Testing emissions levels This was a serious issue requiring immediate attention, as continued driving could damage the catalytic converter. The repair took one full day at the shop. After fixing it, fuel consumption returned to normal and the check engine light cleared permanently. Worth noting that O2 sensor issues often get misdiagnosed as something more serious, so getting a proper diagnostic is important.

Thanks for sharing your experience. That sounds exactly like what I am dealing with on my SQ5, especially the increased fuel consumption and malfunction indicator light. The similarity in symptoms with the faulty oxygen sensor and car components is really helpful. Do you remember the total cost for your repair? My local shop tends to charge premium rates, so having a ballpark figure would help me avoid overpaying. Also, has everything been running smoothly since the repair, or have you noticed any other exhaust system issues?

Just got everything sorted with my SQ5 exhaust system issue. Good news, the problem was simpler than initially feared. The mechanic found a damaged cable connection to the oxygen sensor heater element, which was causing the check engine light and fuel consumption problems. The repair cost came to 95 Euro, which included fixing the faulty wiring and testing the vehicle emissions system. This was much better than potentially needing a full sensor replacement. Since the repair last week, fuel consumption has returned to normal and the check engine light has stayed off. All car components are working perfectly now, and the exhaust system is performing as it should. No other issues have surfaced. Sometimes these problems really come down to basic electrical connections rather than requiring expensive part replacements.

I finally got my SQ5 fixed last week and wanted to share my experience. After getting multiple opinions, I found a reliable shop that correctly diagnosed the faulty sensor issue. The mechanic showed me the corroded oxygen sensor and explained how the heater element failure was causing my high fuel consumption. They also found some minor wiring issues near the sensor. The malfunction indicator light turned off immediately after they completed the work. Total repair cost was 320 Euro, including: New oxygen sensor, Labor for installation, Diagnostic testing, System reset The car now runs perfectly, fuel consumption is back to normal and no warning lights. The repair took about 3 hours. While the cost was higher than some quotes shared here, the thorough work and proper car components used were worth it. Much better than risking further damage to the exhaust system with a cheap fix. Looking back, I am glad I asked for advice here first. It helped me understand the issue and negotiate a fair price for the work needed.