Audi Q2 O2 Sensor Issues Driving Up Fuel Costs

Having dealt with similar symptoms on my 2021 Audi Q3, I can share my experience as someone with moderate car maintenance knowledge. The malfunction indicator in my case was also triggered by sensor testing that revealed issues with the air-fuel ratio. After initial diagnosis, it turned out the problem wasnt the oxygen sensor itself, but rather a faulty connection in the wiring harness leading to the sensor. The repair involved: Complete diagnostic scan, Testing sensor connections, Repairing damaged wiring and plug, Clearing vehicle emissions codes, Final testing to confirm fix Total repair time was about 2 hours and cost 95 Euro. The workshop found that moisture had caused corrosion in one of the plug connections, affecting sensor readings. Before jumping to replacing the entire sensor, which would be much more expensive, you should have the wiring and connections checked thoroughly. Many times these issues are connection-related rather than sensor failure. To better assist, could you share: Current mileage, When the problem first appeared, Any other warning lights or symptoms, Whether fuel consumption changed suddenly or gradually, If youve had any recent maintenance work done

The check engine light appeared after reaching 59626 KM. I appreciate the detailed response about the wiring issue. My last service was just 2 months ago where they performed routine maintenance, but no sensor testing was done. The fuel consumption increase happened quite suddenly, went up by about 25% within a week. This really has me leaning toward checking the wiring first before replacing the whole sensor assembly. The fact that you solved a similar vehicle emissions issue with just a wiring repair is encouraging, especially considering the cost difference. The malfunction indicator has been steady, not flickering, if that helps with diagnosis. Will schedule a diagnostic scan next week to check those connections. Thanks for the repair cost reference point, helps set expectations.

Thanks for providing those additional details. That sudden 25% jump in fuel consumption matches exactly what I experienced with my Audi Q3. The steady malfunction indicator is actually a good sign, when I had a completely failed sensor, it would flicker. The mileage you mentioned is still quite low for a complete sensor failure. Given that you had recent maintenance, its worth checking if any connections might have been disturbed during that service. In my case, the air-fuel ratio was similarly affected right after routine maintenance. Quick tip from my experience: When the workshop does the diagnostic scan, ask them to specifically check the connector near the exhaust manifold. This was the exact spot where my wiring had corroded, and its a common trouble area that affects vehicle emissions readings. I initially considered replacing the entire oxygen sensor at 400 Euro+, but the wiring repair ended up being the right call. If they find similar connection issues, you should be looking at a repair cost closer to what I paid (95 Euro range). Would you mind updating the forum once you get the diagnostic results? It would help other owners facing similar check engine light issues.

The check engine light appeared after reaching 59626 KM. I appreciate the detailed response about the wiring issue. My last service was just 2 months ago where they performed routine maintenance, but no sensor testing was done. The fuel consumption increase happened quite suddenly, went up by about 25% within a week. This really has me leaning toward checking the wiring first before replacing the whole sensor assembly. The fact that you solved a similar vehicle emissions issue with just a wiring repair is encouraging, especially considering the cost difference. The malfunction indicator has been steady, not flickering, if that helps with diagnosis. Will schedule a diagnostic scan next week to check those connections. Thanks for pointing out the specific connector near the exhaust manifold as a common problem area. Its helpful to know what to ask the mechanic to look for. With the potential cost being closer to 95 Euro versus 400 Euro+ for a new oxygen sensor, starting with the wiring check makes even more sense. Ill definitely post an update once I get the results from the diagnostic scan. Thanks for helping narrow down the likely causes rather than jumping straight to sensor replacement.

I have a 2019 Audi Q2 1.6 diesel. When I fill up the tank I find that the fuel is not reading on my alarms. The full tank graphic on the alarms is still maxed out. The odometer reading after refueling for range was 840 and it won't budge. Thank you for the reply.

(Translated from Czech)

It sounds like there might be an issue with the fuel level sensor or the fuel gauge itself. Start by checking the fuse related to the fuel gauge to ensure it's not blown. If the fuse is intact, the problem could be with the fuel level sensor in the tank, which might be stuck or malfunctioning. If you're not comfortable checking these components yourself, I recommend having a mechanic inspect the system to ensure accurate fuel readings. Let us know how it goes or if you have any further questions!