BCU dead Repair Question

Hi all, I'm new to the forum and am hoping someone can help me with my td5. Having owned several 300tdi's over the years and loving them to bits I had the opportunity to pick up a clean td5 with starting issues for next to no money. It turns out that the cars BCU is dead I think, the car has a B with a line through it flashing on the dash and will start run for 3 sec then cut out, you then have to wait a few minutes before it will once again start run then stop. My questions are;

1) am I right in thinking the bcu has a fault?
2) could this purely be the bcu and ecu of the vehicle being out of sync (and if so how's that done?)
3) I know the bcu, key and ecu need to be matched, and if I was to purchase a second hand unit I would need someone with nanocom to help me out, however if I was to change the bcu, key fob and ecu all from the same vehicle as one job lot would that work without the need for programming (I have a friend that breaks td5's)
4) if answer to question 3 is "no" does anyone have nanocom anywhere near the Chester area that could help me out?

Sorry for the long post, I've seen the super friendly help you guys give each other on this site and am hoping someone can help me, times are hard and I hope I haven't bought a money pit or scrapper!

Cheers!
Lee

Td5newbie said:

I've seen the super friendly help you guys give each other on this site

Click to expand...

But that's only after you have introduced yourself in the 'Introduce Yourself' section

ps - don't know the answer to your Q

Kwakerman said:

But that's only after you have introduced yourself in the 'Introduce Yourself' section

ps - don't know the answer to your Q

Click to expand...

I agree pal sorry! I've introduced myself now

Td5newbie said:

Hi all, I'm new to the forum and am hoping someone can help me with my td5. Having owned several 300tdi's over the years and loving them to bits I had the opportunity to pick up a clean td5 with starting issues for next to no money. It turns out that the cars BCU is dead I think, the car has a B with a line through it flashing on the dash and will start run for 3 sec then cut out, you then have to wait a few minutes before it will once again start run then stop. My questions are;

1) am I right in thinking the bcu has a fault?
2) could this purely be the bcu and ecu of the vehicle being out of sync (and if so how's that done?)
3) I know the bcu, key and ecu need to be matched, and if I was to purchase a second hand unit I would need someone with nanocom to help me out, however if I was to change the bcu, key fob and ecu all from the same vehicle as one job lot would that work without the need for programming (I have a friend that breaks td5's)
4) if answer to question 3 is "no" does anyone have nanocom anywhere near the Chester area that could help me out?

Sorry for the long post, I've seen the super friendly help you guys give each other on this site and am hoping someone can help me, times are hard and I hope I haven't bought a money pit or scrapper!

Cheers!
Lee

Click to expand...

more info here http://www.landyzone.co.uk/lz/2990756-post3.html

as about questions

1 = 90% yes
2 = yes but not with ECU with IDM
3 = no, you need tester either way

Do you have the EKA (Emergency key access) code as this should bypass the immobilisation if you follow the sequence in the hand book, it is designed to overcome issues with the RF and passive reader which the BCU utilises to validate the key? BCU's do fail but not a frequent known problem (I have one on my desk which I am debugging to try and fix going forward as I already do with ECU's) the starting for 3 seconds is normal and the ECU will start the engine even without validation of the learned security code from the BCU but only for 3 seconds. The BCU synchronizes on a dedicated wire between the ECU and BCU, this wire is also used to provide authorisation to mobilise on the key once validated.

A Nanocom is what you require as this will tell you the immobilisation status from the ECU,also check the RF to key process to BCU. If it is the passive reader on the steering column this can be de-activated ( I believe) using the Nanocom, unfortunately I am in Dorset.

A key question is are all of the electrics working such as windows and wipers as these are all controlled by the BCU through the serial bus back to the IDM? If so then it is likely to be the RF or passive reader on the steering lock. The EKA process should identify if a fundamental problem exists or simply find someone locally with a Nanocom. The good news is that all BCU hardware and firmware should be backward and forward compatible, you may need the key that was with the BCU just in case the Nanocom gets locked out.