Mini Roadster Oxygen Sensor Heater Failure

Oxygen sensor issues on these cars can be tricky. I had a similar problem with my Mini. Check engine light, rough idle sometimes, the works. Before you start replacing sensors, have you checked the wiring and connectors to the oxygen sensors? Sometimes, it's just a loose or corroded connection that's throwing the code. Think of it like a loose wire on a light bulb – the bulb itself might be fine, but it won't light up if the connection is bad. Which oxygen sensor is throwing the code, by the way? Pre-cat or post-cat?

Thanks for the insight. I did a visual inspection of the wiring, but didn't see anything obvious. The error code points to the pre-cat oxygen sensor, specifically the heater circuit. Is there a good way to test the wiring harness or connector to confirm?

Ah, the pre-cat sensor. That makes sense with the fuel consumption. If the heater isn't working, the sensor takes longer to reach operating temperature, and the engine management might run in open-loop longer, using a richer mixture. Honestly, without proper sensor testing tools, chasing wiring gremlins can be a real pain. If you aren't comfortable probing the connector, I'd suggest taking it to a trusted shop. 95€ sounds like a fair price to diagnose and repair a connection issue. Better than throwing parts at it and hoping for the best.

Just got the Mini back from the shop. As suspected, it was a faulty connection on the oxygen sensor. They cleaned it up and secured it properly. Check engine light is off, and hopefully, the fuel consumption will return to normal. Thanks for the tip!