No OBD coms or pre heat. 2005 2.0HDI

[Megadodo]

As payment for some work I did, I was given a 2005 2.0 HDI Berlingo van with stellar mileage. Apparently the "heater core leaked so it loses coolant, the carpet gets wet!" according to the PO. I specialise in repair of BMW and MINI repair so it was a bit of a risk but a project and potential learning experience. As it turned out the damp carpet was from a badly fitted roof aerial and the coolant loss was due to a failed head gasket. This was repaired, engine out but an easy enough job, and the engine went back in and initially started and ran fine. After about 300 miles it went into limp mode that cleared after a cool down and restart. Also the preheat light has never come on even with a new preheat relay and 4 new glow plugs. After it went into limp mode I grabbed my OBD reader that I know works in other Berlingos but it wont talk to the ECU so I have no idea what the cause of the limp mode activation is? 
I'm assuming both of these issues are probably ECU related. Reading through some posts on here it looks like I have to change not just the ECU, but the BSI, key reader and the key chip as well?

[cancunia]

Welcome to the forum.
Does the pre-heat light come on just for a second or not at all? Unless it's very cold, the HDi engines are only using the glowplugs during warm-up rather than needed for starting.

As for the OBD issue, have a read through here...

https://www.berlingoforum.com/thread-20483.html

[Megadodo]

No light at all, even when there was snow on the ground.

[cancunia]

No light at all, even when there was snow on the ground.

Not even for just a second when you first turn the key?

[Sol]

You could have a blown fuse, there are some for  "Diagnostics" in the engine bay fusebox as well as large master fuses hidden under the top tray of regular fuses in that box. Also you could have water in the BSI and it's faulty now. The diagnostic socket goes to the BSI first, then it in turn, connects you to the other ECUs. (ABS, engine ECU, Airbag system etc)

You can buy a virginised BSI and reprogram it using DiagBox and a laptop but nothing else can do that.

If you had to replace it with a used one from a breaker without virginising it then yes, much hassle finding an exact replacement set, then you have to swap ECU, BSI and keys together etc. Can't code your keys to a different used BSI unless virginised.

For anything more than reading codes, OBD readers are limited use on these vehicles but if the BSI got wet and the CANBUS or VANBUS is not communicating properly then it may not be possible to connect but I'd check all of the fuses properly first before committing money to BSI swaps etc.

With all due respect, I guess this person didn't do you much of favour giving this van to you. But have to give you credit for cracking on with it.

Test every fuse thoroughly including the hidden ones under the top fuse tray before you go further. It will probably be riveted in on your model. If all are definitely good, then I'd dig the BSI out of the dash  and see if it's soaked inside from the aerial leak.

It also has fuses on it. Check those too if the others draw a blank.