Citroen C1 O2 Sensor Connection

Interesting issue. I had similar symptoms with my 2018 Volvo V60. Error stored, check engine light, and higher fuel consumption. In my case, it was a defective cable or plug connection to the sensor, effectively giving it bad data. This skewed the air-fuel ratio and wrecked my fuel efficiency. Think of it like a short circuit messing with your car's brain!

Thanks for the insight! The cable or plug connection... where should I be looking? Is there a specific area that's prone to failure?

On the Volvo, the connection issue was near the catalytic converter, where the exhaust heat was taking its toll on the wiring. Think of bending a paperclip until it snaps. The heating and cooling cycles weaken the connection. The location might differ on the C1, but inspect any connections close to high-heat areas. I strongly suggest visiting a workshop to get an expert opinion and perform voltage tests, to not damage the sensor or ECU. A mechanic will likely pinpoint the problem quickly.

Thanks for the help. The workshop confirmed it was a faulty O2 sensor connection, just like you suspected. Replaced it, cleared the code, and it's running great now! Repair cost was 95€.