last posts

The safe procedures to disconnect and reconnect the BSI

In peugeot and citroen marks or group PSA there is different models of BSI . Although this modules are different, they use the same connectors and many of the pins have the same purpose.

BSI is a computer and responsible on many functions in car. Be aware that certain procedures must be followed when disconnecting and reconnecting power to the BSI to avoid corrupting the software code and losing settings and data.

Failure to follow these simple rules can result in loss of configuration or failure of the BSI. Recovery can be very costly and time consuming.

when will be the BSI activated

The BSI can be activated by enabling certain functions such as a press remote key, an open door, or a radio on. In this case, the module (BSI) immediately switches to full operating mode.

When the ignition is turned off, the Unit continues to operate for 2 minutes and then switches to 'Standby'/'Power Save' for the next minute. In this case, it consumes a current of about 0.02A (20mA). However, if the driver turns on any equipment, the BSI operates for 30 minutes in Economy Mode.

Any loss of power to the BSI while it is active can cause the problems mentioned in the introduction.

To prevent this from happening, remember the "Three Minute Rule"!

Disconnecting the Battery (Three Minute Rule)

Whenever disconnecting the battery (battery) is required, turn off all interior lights and other equipment, close all doors and roll down the driver's window (to allow access to the passenger compartment through it).

Turn off the ignition and remove the key from the ignition lock, and also disconnect any scanner from the service socket OBD, if it is connected.

Wait a full 3 minutes before disconnecting the battery (After three minutes, the Unit's power relay can be heard clicking).

BSI should be allowed to sleep, i.e. go into Economy Mode. Do not operate any equipment during this time. Remember, even opening the hood will wake up the BSI on a vehicle equipped with an alarm or engine compartment lighting. 

If the battery is under the hood, open the hood first. In Peugeot 807, you can disconnect the battery through the driver's window, only first open access to it by opening the floor covering.

Always disable any scanner ,because the BSI does not go to sleep when the diagnostic computer is connected. Make sure the remote key for the same Peugeot model is not used near your vehicle as this can also wake up the BSI.

Connecting the Battery

You should always perform the following procedure when connecting the battery, referred to as a 'Soft Reboot', to minimize the possibility of damaging the BSI.

Ensure that the battery disconnection procedure is followed and that all BSI functions have been turned off with the driver's window open.

  • Close all doors on the vehicle.
  • Remove the key from the ignition lock.
  • Connect battery.
  • Wait 10 seconds.
  • Turn on the headlights through the driver's window. You will hear the sound 'Bom'.
  • Turn on the ignition, the vehicle's systems will be activated and tested.

After connecting the battery: If a BSI-managed vehicle function, such as interior lighting, is on, there is a possibility that the BSI configuration and program may fail or be corrupted.

Remember: to avoid a power surge, always connect and disconnect the ground wire first.

Following the sequence, connect the large gauge wires to the battery of the donor car, and then connect them to the battery terminals of your car (the ignition must be turned off) and then start it.

Wait a few minutes of idling for the battery charge current to stabilize. Do not increase engine speed.

Turn on powerful consumers of electricity: headlights, heated rear window and heater fan.

Disconnect the wires from the battery (first the ground wire, then the positive one).

Sequentially switch off the previously switched on consumers.

Do not turn off the engine and let the battery recharge.

The inclusion of powerful consumers protects against high voltage surges when the wires are disconnected.

 Procedure for disconnecting and connecting BSI.

  • When a BSI is disabled, it is desirable to save or write down its configuration.
  • Disconnect the battery following the 3 Minute Rule.
  • Disconnect all connectors from the BSI.
  • Remove the BSI to perform the necessary service operations, and then install it back.
  • Connect all connectors to the BSI (battery must be disconnected!)
  • Connect the battery following the steps above.

 Replacing the BSI.

  • Follow the procedure for disabling the BSI, steps 1,2 and 3. Observe the 3 Minute Rule.
  • Replace BSI.
  • Connect the battery, open the door and turn on the ignition.
  • Connect DIAG 2000 and download the latest BSI software (except Peugeot 406, whose BSIs must come with the latest software).
  • Carry out the BSI Configuration/Initialization, following the '
  • BSI Calibration Procedure after Download'.

 Please note:

 When replacing, the BSI may come with older software versions.

You must download the latest software before replacing and starting the initialization and configuration of the BSI, except for the Peugeot 406 BSI which cannot be downloaded.

You must adhere to the 3 Minute Rule. Failure to follow this rule may result in the BSI not working when accessing the engine and vehicle control ECUs. Remember that you only have three attempts to calibrate the engine control ECU to BSI.

The battery must be fully charged, otherwise initialization and configuration may fail.


Font Size
lines height