BSI = Built-in Systems Interface
The BSI unit is basically a computer which handles a multitude of functions such as odometer value, central locking, lights and immobiliser. Some later BSI units are liable
to corrupt their own software program if not "woken up" in a specific way after programming keys or battery disconnection.
Process of Rebooting the BSI in a Peugeot:
- Unplug any diagnostic tools from the vehicle.
- Make sure all the gadgets are switched off, the driver's window lowered and open the bonnet.
- Then close the doors but don't lock them - and take the key out of the ignition.
- Wait for 3 minutes, disconnect a battery terminal and wait for a further 15 seconds.
- Re-attach the battery terminals and wait a further 15 seconds keeping the doors closed.
- Turn the side lights on through the open driver's window.
- Switch on (don't start) the engine and check everything works.
- With the key in the ignition, press and hold down the lock button on the key for 10 seconds. This should re-establish the link between the security system and the key.
- Check the central locking system by unlocking and locking the door consecutively.
- Start the engine and finish checking everything works.
Any other procedure could cause malfunctioning of different units which depend on the BSI.
If your car won't start or the doors won't work even after a reset, try removing the link HS (or SH) in the BSI for 15 minutes and then replace it. This may also reset some of the preferences but should at least get you going!
The BSI and the ECU MUST be matched together with the key fob remote PCB and key fob transponder. It is not possible to fit a second hand BSI to a Peugeot unless the other items are replaced as a complete set.
- The engine ECU and the BSI have to be matched.
- Each ECU in a correctly functioning system has a 4 digit code programmed into it.
- Once this code is entered into the ECU it will not be possible to be read, deleted or modified.
- The second hand BSI can't be matched to the existing engine ECU even if you know both codes from both ECU's.
- In order to fit a new BSI you need to know the correct security code of the existing engine ECU so you can enter this code in the new BSI.
- If you get this wrong the new BSI will become unusable.
- If you don't know the correct code for the existing engine ECU then you need to replace the engine ECU and the BSI.
- They then will need to be configured and matched. If the code to the vehicle is not known you can make up a code in this case but make sure you enter the same code in both ECU. It could be an expensive exercise to get this one wrong.
- Peugeot Dealers can obtain the security codes for a particular vehicle if you are the lawful owner.
- The odometer reading (distance travelled) is memorised in the BSI and the instrument panel. If you connect a second hand BSI with a reading higher then the one on the instrument, the distance on the instrument will increase to the higher BSI reading as soon as it is connected to the car.
- So beware, a customer would not be happy if his distance suddenly jumped up several thousand miles/kilometres.
- There is one way you can fit a second hand BSI. Use the engine ECU from the same donor car where the BSI came from.
- It would then still be helpful if you can obtain the donor cars 4 digit security code for future programming, and also remember the issue with the distance. The distance reading won't be a problem if the donor car has lower distance then the recipient, the distance in the BSI will then simply go up to the correct distance.
Repair is an alternative for replacement of the BSI
see the BBA Reman information here