Engine won't start after BSI swap

Hi !

Do I need a password to be connected to the BSI (BodySystemInterface)
via the OBD interface to read out the immobilizer code ?

( I dont have ANY codes for my Citroen C3 car - VF7FCKFVB26006169)

I have changed the old BSI unit with a new unit because of fault with communication to instrumentpanel.
OBD fault code DTC : U0028 ( error bus A communication)

Now the car won't start because of immobilizer.

Kind reg. Rune S. - Norway

I am not sure every one else that I know of had to replace the ecu and the key fob because no one knows if that is possible I will see if I can find any or did they give you a engine code with the part

Hi !

The new BSI unit are from same model C3, 2002, 1.4 petrol with VIN no : VF7FCKFVB26029345 and this unit are working perfect,
exept the immobilizer code from the new BSI are not matching with code in flash-eprom in ECU (EngineComputerUnit) I think, but I'm not sure about all this ?

reg. Rune S. - Norway

jmitchell91 wrote:every one else that I know of had to replace the ecu and the key fob

This is correct, you need to change ECU and BSI together from the same donor for second hand (used) parts.

A virgin BSI, from citroen (brand new) is a different story as this can be 'paired' to the engine ECU when its fitted using lexia via OBD

runsun wrote:Do I need a password to be connected to the BSI (BodySystemInterface)
via the OBD interface to read out the immobilizer code ?

It is not possible to re-code an already coded BSI using OBD/lexia or read out immo code.

runsun wrote:Now the car won't start because of immobilizer.

Correct. You need the engine ECU and fob transponder chip and its matching BSI to start.

This is why many people choose to have their BSI repaired or swap ECU BSI and Transponder parts together


You options would be

to find the ECU that went with that BSI

or

find someone who can 'immo off' your Engine ECU

or

find someone who can strip down the BSI and transfer over the identity (memory chip) from your broken BSI to working BSI.

2 and 3 will require some serious technical and soldering skills and I don't know how successful these jobs are

Thank you for useful answers !

Question : Do I need the box into the battery case who are marked with "PSA Calculator" in addition to the ECU or can I use the old PSA Calculator box.

(What function has this box ?)

Reg. Rune S. - Norway

Hi again !

I forgotten to tell that the car are running well with the old defective BSI, remote control, lights and door-centrallocking are function normally,
but the instrumentpanel with warninglights, speedometer, rpm, eng.temp and gas.level does NOT function.

Kind reg. Rune S. - Norway

runsun wrote:I forgotten to tell that the car are running well with the old defective BSI, remote control, lights and door-centrallocking are function normally,
but the instrumentpanel with warninglights, speedometer, rpm, eng.temp and gas.level does NOT function.

It may be better to get yours Repaired by BBA Reman

runsun wrote:Question : Do I need the box into the battery case who are marked with "PSA Calculator" in addition to the ECU or can I use the old PSA Calculator box.

(What function has this box ?)

I don't know what these are, have you found them in Diagbox?
It is the Power Steering ECU. No, you don't need to replace this because it is not coded to the car.

runsun wrote:Question : Do I need the box into the battery case who are marked with "PSA Calculator" in addition to the ECU or can I use the old PSA Calculator box.

Power steering ECU, you don't need to change this if you are swapping out the engine ECU and BSI module