BSM Swap: Siemens L06 to Delphi L11 - Citroen C4 (2005)

[navnet]

Hi everyone,

I have a 2005 Citroen C4 1.6 HDi (110 bhp) which recently suffered the common BSM failure – the power supply to the cabin blower motor went dead. As a temporary fix, I’ve bypassed it by running a new fused feed from the main M8 power stud on the BSM to the blower wire at the PP1 NOIR connector.

Everything is working now, but I’ve managed to get a replacement BSM from a functional car. Here are the details:

Original BSM: Siemens L06

Replacement BSM: Delphi L11 (sourced from a 2008/2009 Peugeot, likely a 207)

All the plugs and sockets look identical. My question is: will the L11 unit be fully compatible as a plug-and-play replacement for the L06?

Thanks in advance for your help!

[mickthemaverick]

I cannot give a definite opinion here, I would be surprised if it was fully compatible and hopefully one of our members with in depth knowledge of these will be able to advise you. I can say that rather than 'plug and play' you may have to do some programming but I am not sure. Good luck

[navnet]

Thanks for the reply. I'm aware that while the BSI requires coding/pairing, the BSM is just the under-bonnet fuse box and is essentially a non-programmable unit, though it may have a different internal configuration. I've seen opinions on various forums that 'L' series modules are interchangeable as long as you use a unit with a higher number (e.g., replacing an L06 with an L11). However, I’m not sure how the vehicle's production year affects this compatibility.

[RichardW]

There are loads of different units, all with slightly different configuration, so it's usually best to stick with one that has the same number stencilled on it. However, it's pretty easy to change, and as you say not programmed, so you could just plug it in and see if all the functions work as intended.

[navnet]

After installing the L11 unit, an airbag fault is displayed and the starter motor won't engage. As I mentioned, I was told this L11 came from a functional donor car, but I can't be 100% sure of its condition. This is why I'm questioning the compatibility. Physically, all the connectors are a perfect fit.
I’d appreciate input from anyone with experience in BSM swaps: which versions are interchangeable, and were there any changes in pinouts or device control logic between different production years?

[shtu]

Your best bet is to look at the parts lists of suppliers of new items, there's usually compatibility lists there, eg, couple of random ones,

https://d2pautoparts.com/products/under ... 9807028780
https://www.leadercomponents.com/produc ... x-bsm-new/