Built-in Sytems Interface Unit

(BSI Unit)




Welcome to our BSI Unit area, we have provided a description on BSI Units and the services we offer for BSI Units. 


What is a Built-in Systems Interface Unit?

A Built-in Systems Interface unit - Commonly known as a BSI Unit is an ECU (Electronic Control Unit) that includes the following:

Control Electronics - The BSI controls communications between the ECU's on a vehicle. 

Interface Electronics - Relays, Diagnostic Socket, HF Reciever, Fuses. 

Calculation Electronics - This is what controls basic functions such as Signalling, Locking and unlocking of doors, Visibility, Interior lights, Engine immobiliser etc... 

Location for vehicle information for anti-theft protection - Key codes, VIN Code/Number, Radio identification, HF Remote Control Code. 

A Program which is needed to perform diagnostics, configurations, and to control the system. 

At French Diagnostic Services we have the latest Peugeot Citroen and Renault main dealer diagnostic equipment. We have 20 years experience on conventional 12v wiring to the latest multiplexing technologies with Can, Van, Lin and other networks that run side by side to communicate all over the vehicle. Therefore we are able to carry out procedures such as Programming and configurations. Here at FDS we can supply and fit new BSI Units or repair your BSI Unit if it is repairable. 

When booking your car in always remember to bring all keys that belong to the vehicle and the confidential code card - this is usually supplied with the vehicle when new, dont panic if you dont have one as we are able to obtain the transponder code from the main dealer who will require a small charge. The transponder code is needed to be able to programme and initialise the BSI to all the other ECU's.


If you have any further queries regarding BSI Units, please contact us.