Citroen C2 Oxygen Sensors

Consumption climbing, the engine lamp on and the idle turning rough is the usual trio, often with black smoke and a sulphur smell as the mixture runs rich. The important point is that a fault code naming the sensor does not always mean the sensor is bad — an exhaust leak ahead of it produces identical readings. A scan tool showing live sensor voltage switching is what actually confirms it.

Sensors run R1,200 to R3,350 through our supplier network, including Bosch units. Fitted at an independent, add R500 to R950 in labour, and be aware that a sensor which has been in a hot exhaust for a decade sometimes has to be cut out rather than unscrewed. Send the engine code and tell us whether you need the upstream or downstream sensor — they are different parts.

Briefly. Without a usable signal the ECU falls back to a fixed open-loop fuelling map that deliberately errs rich, which is safe for the engine and very bad for the catalyst — unburnt fuel reaching a hot converter destroys the substrate. A catalytic converter is R15,000 and up, against a sensor at a fraction of that. This is a repair worth doing in the same week you find it.

Original sensors on the C3, Xsara and C3 Aircross petrols generally manage 100,000 to 150,000 km. Cheap unbranded replacements often fail inside two years, because the sensing element and the heater circuit are exactly where the cost is cut. Bosch or Denso units match original life. If you are replacing one at high mileage, doing both the upstream and downstream sensor together makes sense — they are the same age.

Pro Citroen Spares sources new Bosch sensors for the C3, Xsara and C3 Aircross, with alternatives through our supplier network. Send the engine code rather than the model, because the same car can take different sensors depending on the emissions specification it was built to. We will also confirm the connector type, which is the detail that most often makes a correct-looking sensor unusable.