Second Hand Peugeot 308 Lambda Sensor

Lambda sensors exist on petrol-engined 308s across both the Mk1 (2007–2013, facelifted 2011) and Mk2 (2013–2021, facelifted 2017) generations, as they are part of the catalytic converter management system on petrol engines. Diesel 308s do not use a traditional lambda sensor in the same way, as diesel engines manage emissions differently and rely on systems such as EGR and DPF rather than a stoichiometric oxygen sensor. If you have a diesel 308 and are chasing an emissions or sensor fault, confirm with the breaker what sensor you actually need against your registration.

These two cars sit in different generations — the 2010 car is a Mk1 (2007–2013) and the 2014 car is an early Mk2 (2013–2021) — and the platform, engine range, and exhaust systems changed substantially between them. Even if the connectors look similar, the sensor calibration and positioning can differ, and fitting the wrong era sensor can cause running issues or an MOT emissions failure. You should confirm against both engine codes with the breaker before buying.

Trim level does not affect which lambda sensor you need — the sensor is determined by the engine code and emissions era, not whether the car is an Access, Active, Allure, or GT. All trims within the same generation using the same engine and fuel type will share the same sensor specification. Just make sure you match on engine code and model year rather than trim name, and the breaker can cross-reference this against your registration.

Petrol 308s typically have at least two lambda sensors: an upstream (pre-cat) sensor and a downstream (post-cat) sensor, and these are not interchangeable with each other even from the same car. When sourcing a used sensor, tell the breaker clearly whether you need the upstream or downstream sensor, as well as your engine code, so they can pull the correct unit. Getting the position wrong means the engine management system will read incorrect data and the fault will not clear.

The Mk2 308 was facelifted in 2017, which brought some engine and emissions updates, so a sensor from a pre-facelift Mk2 (2013–2017) may not be a straight swap onto a post-facelift car even within the same generation. The safest approach is to provide the breaker with your exact engine code and registration so they can confirm whether the part from their donor vehicle matches your specification. Never assume year-range compatibility across a facelift boundary without that check.

Lambda sensors from other PSA-group vehicles or even non-PSA cars can sometimes share the same connector, but the thread pitch, body length, and calibration still need to match your specific engine and exhaust system. A visually identical plug is not sufficient confirmation of fitment, particularly across Euro 5 and Euro 6 emissions boundaries where sensor behaviour differs. Always cross-reference by engine code with the breaker rather than relying on physical appearance alone.