There are basically only 2 reasons you why need to "code in" an ECU. 1) for "security" (I use the term loosely) and 2) add it to a "closed system".SiriusHardware wrote: ↑Wed May 04, 2022 7:17 pm Hi Arfur - surprised you say that, about there being no need to code the wiper / stalk box on the 107 and also implying the same about the C3, I was pretty sure the 'stalk box' around the steering wheel column was one of various ECUs dotted around the C3.
There are 2 forms of security. One reduces the likely hood of your car being stolen/rebirthed. The other secures the wealth of the car manufacturer.

Manufacturers like BMW and Mercedes (and some others) require every ECU to be coded into the system...because they can. It's to protect their "intellectual property" (read: no DIY or third party).
The COMs unit (switching stalks) is not secure and is already a part of the permanent (closed) network. That is; the network is expecting one to be there. However something like an optional extra (like a CD stacker or sat nav) needs to be coded in because it's not "normally" part of the network.
On that year model, PSA does not require the COMs to be "coded". On future models however, watch this space, to protect their "patch", one day, they may change their mind!