Second Hand Peugeot 408 Alternator

The Peugeot 408 sold in the UK runs as a single generation, so the most important thing to check is that the engine code on both vehicles matches, not just the year. The engine code is printed on your V5C or can be pulled from a VIN check, and it tells you far more about alternator compatibility than the model year alone. That said, confirm with the breaker against your registration before buying, as ancillary and mounting details can vary mid-production even within the same engine family.

Trim level makes no difference to alternator fitment on the Peugeot 408 — whether your car is an Active, Allure, or GT Line, the alternator is determined by the engine, not the badge. What you might notice is that breakers' cars may carry different cosmetic parts depending on trim, but the alternator itself will be the same unit for a given engine code. Give your engine code to the breaker and let that do the work, not the trim name.

The engine code is the single most useful detail you can supply to a breaker, sitting above fuel type, year, or any other detail when it comes to alternator fitment. You'll find it on your V5C logbook or via a VIN check through a service like the DVLA or a dedicated VIN decoder. Petrol and diesel units will not interchange, so at minimum confirm both the engine code and fuel type before agreeing a price with the breaker.

No — petrol and diesel alternators are not interchangeable on the Peugeot 408 even if the cars look identical from the outside, as output rating, mounting, and wiring configuration differ between fuel types. Always match on fuel type first, then narrow it down further using the engine code to ensure you're getting the right unit. Tell the breaker both details upfront and ask them to check against your registration to be sure.

Stellantis group cars like the 308 and 3008 can share engines and ancillaries with the 408, so a cross-model fit is possible in theory if the engine code is identical. However, alternator brackets, pulley alignment, and wiring plugs can vary between platforms even when the base engine is shared, so you should not assume it fits based on engine family alone. Route this question directly to the breaker with your full engine code and registration so they can verify on their own vehicle before dispatch.

Some modern Peugeot models use smart charging systems where the ECU communicates with the alternator, and whether this applies to your specific 408 and requires any configuration after fitting is something to confirm with the breaker or a Peugeot specialist rather than assume either way. This is not something we can state as fact here because it depends on the exact build spec and software of your vehicle. Ask your fitting garage before purchasing so you're not caught out after the part arrives.