P38A Moving a logic board from lowline to highline BECM

P38DieselOwner · Aug 25, 2025

Hi again everyone, so I have a spare highline BECM, but my car has a lowline BECM and was thinking of just swapping the logic board from lowline to the highline unit but have read on forums it won't work necessarily so I wanted to ask around if anybody had any luck with doing that. Both are taken from manual diesel P38, the highline is from a DSE 1996 and the lowline is from DT 1997.

pwood999 · Aug 25, 2025

It would need all the security stuff copying into the Highline. There are places that can do the cloning. Also unless they relicate the mileage (kilometerage ?) then the Instruments or BECM will update to whichever is higher.

If you have the correct FOB(s) & EKA for the Highline, it would probably work, but the milaeage issue still exists. After you write down the new VIN, EKA, etc. you could disable EKA & Immobiliser just in case.

Datatek · Aug 26, 2025

No point in just swapping the board, if you are going to swap use the whole unit as the relay board on the low line will be different to the high line in that it will lack some components. As pwood999 say's you will need the FOB(s) for the high line, there will likely be a problem with the mileage, the VIN will be incorrect and you will need diagnostics to deal with the EDC immobiliser code.

P38DieselOwner · Aug 26, 2025

Oh thanks to both of you, I hoped that just putting my working logic board from a lowline into a highline and then putting the highline BECM with my lowline logic board in the car would do the trick, but I won't be doing all that just for front fogs.

Grrrrrr · Saturday at 14:22

P38DieselOwner said:
Hi again everyone, so I have a spare highline BECM, but my car has a lowline BECM and was thinking of just swapping the logic board from lowline to the highline unit but have read on forums it won't work necessarily so I wanted to ask around if anybody had any luck with doing that. Both are taken from manual diesel P38, the highline is from a DSE 1996 and the lowline is from DT 1997.

Yes, done it. Worked fine.

Grrrrrr · Saturday at 14:25

P38DieselOwner said:
Oh thanks to both of you, I hoped that just putting my working logic board from a lowline into a highline and then putting the highline BECM with my lowline logic board in the car would do the trick, but I won't be doing all that just for front fogs.

I did that. For some reason the fogs didn't work but I think it was a connector issue because I then put the logic boards back and Marty was kind enough to clone the Highline from my Lowline and we still had sone issues. Cannot remember what it was but Marty spotted it and fixed it. In theory though, plug and play.

Datatek · Saturday at 16:59

Grrrrrr said:
I did that. For some reason the fogs didn't work but I think it was a connector issue because I then put the logic boards back and Marty was kind enough to clone the Highline from my Lowline and we still had sone issues. Cannot remember what it was but Marty spotted it and fixed it. In theory though, plug and play.

Plug & play? You are joking. Diagnostics needed to sync the BECM to the EDC at the very least plus info relating the vehicle will be incorrect. and you will need the FOB's to go with the replacement BECM.

P38DieselOwner · Sunday at 08:40

Grrrrrr said:
I did that. For some reason the fogs didn't work but I think it was a connector issue because I then put the logic boards back and Marty was kind enough to clone the Highline from my Lowline and we still had sone issues. Cannot remember what it was but Marty spotted it and fixed it. In theory though, plug and play.

Hi, so if I understand correctly you have a lowline logic board in a highline BECM and it worked just by swapping the logic boards? Because I am confused as others mention the keyfob sync but I thought that the codes for the fob are in the logic board.

Datatek · Sunday at 09:59

P38DieselOwner said:
Hi, so if I understand correctly you have a lowline logic board in a highline BECM and it worked just by swapping the logic boards? Because I am confused as others mention the keyfob sync but I thought that the codes for the fob are in the logic board.

FOB sync is not a problem, engine ECU to BECM needs diagnostics, there are problems with recorded mileage and VIN etc

Grrrrrr · Monday at 14:04

Datatek said:
FOB sync is not a problem, engine ECU to BECM needs diagnostics, there are problems with recorded mileage and VIN etc

They're all on the logic board aren't they? I don't recall any issues.

Datatek · Monday at 15:55

Grrrrrr said:
They're all on the logic board aren't they? I don't recall any issues.

Maybe you have forgotten.

Grrrrrr · 2025-09-02T06:53:16+0100

Datatek said:
Maybe you have forgotten.

Quite possibly!

From memory I think the logic board holds all the information required though. The powerboard is just relays and mosfets and whatever.

Datatek · 2025-09-02T07:24:28+0100

Grrrrrr said:
Quite possibly!

From memory I think the logic board holds all the information required though. The powerboard is just relays and mosfets and whatever.

Correct.

RangeRoller dt · 2025-09-03T00:04:24+0100

I had a lot of stuff on my DT that you don’t usually have. I’m pretty sure it was a low line becm with fogs? Not sure how but all seemed OE and functional. Always guessed it was a manual/auto thing because of the cooler differences

P38A Moving a logic board from lowline to highline BECM

P38DieselOwner

Member

pwood999

Well-Known Member

Datatek

Well-Known Member

P38DieselOwner

Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

P38DieselOwner

Member

Datatek

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

RangeRoller dt

Well-Sprung Member

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