Peugeot 307 light flicker

[Pasty PFC]

I have heard that it is not possible to replace the BSI unit alone. Apparently they are coded to work with only the ECU it is paired with. Does anyone know if this is true?

[GiveMeABreak]

Don't get your Engine Fuse Box mixed up with your BSI unit. The BSI is normally found on the inside of the car and usually inside a compartment near the passenger side glovebox on a RHD. It will usually incorporate several banks of passenger compartment fuses too.

To answer your question, yes you need a matched BSI, Engine ECU and the Transponder Chip contained in the key fob. You can't replace these individually as they are a matched set.

[Pasty PFC]

I took the plunge and bought a new OEM coms unit. Problem solved.