Second Hand Peugeot 306 ECU

Yes, every Peugeot 306 has an ECU regardless of engine or fuel type — both petrol and diesel variants use one to manage engine functions. The 306 was produced from 1993 to 2002, with a facelift in 1997 that updated styling and some mechanical details, but ECUs were fitted throughout the entire production run. Whether you have a carburettor-era early petrol or a later common-rail diesel, there will be an ECU to replace.

The 1997 facelift is a significant boundary and the safest approach is to match ECUs within the same phase of production rather than crossing it. Engine code is the most important detail here — even if two cars share a fuel type, changes to engine management mapping mean a pre-facelift ECU may not be compatible with a post-facelift car. Name the boundary to your breaker and have them confirm fitment against your specific registration and engine code before buying.

Yes, the engine code matters above everything else when matching a 306 ECU — it determines the exact management system and software mapping the unit was built for. The engine code is printed on your V5C or can be confirmed via a VIN check, and it is the single most useful detail you can give a breaker. Two 306s from the same year can have completely different ECUs if they run different engines, so always lead with the engine code when requesting a quote.

Trim level does not affect ECU fitment — the ECU follows the engine, not the badge. An LX and an XSi sharing the same engine code will use the same ECU, so you do not need to find a unit pulled from the same trim as your car. The main practical difference between trim levels is cosmetic, so ignore the trim name and focus on matching the engine code, fuel type, and gearbox type (manual or automatic) when speaking to the breaker.

Yes, this matters completely — a petrol ECU and a diesel ECU are not interchangeable and are programmed for entirely different engine management systems. Always confirm you are sourcing a unit from the same fuel type as your car, and back that up with the engine code to make sure the calibration is correct. Fitting the wrong fuel-type ECU will not work and could cause further damage.

ECUs on the Peugeot 306 can be paired to the vehicle's immobiliser, which means a used unit may not simply plug in and function without additional programming. Whether coding is required and what that involves depends on your specific car and ECU variant, so this is something you must confirm with the breaker and a diagnostics specialist before purchasing. A breaker can tell you whether the unit they have was previously coded, but the coding process itself is a separate step you will likely need a specialist to carry out.