Thread: D3 computer issues (the whole bus)

Rubbish situation to be in mate, I feel for ya.

The first thing that comes to mind with everything carrying on, but still having something going over the lines is maybe its power related. You've replaced the battery, so that eliminates that. It was about off, any chance you've missed some ground straps/cables? Bad grounding can cause all sorts of weirdness.

Is there anyone close to you with a Gap IID Tool? Might be worth giving that a crack, just to see if it has a better chance of connecting to the ECU. Would at least show that there is a comms problem of some sort.

Good luck mate!

Yes - we had a couple of ground issues - this thing has grounds everywhere.
I put a scope on both the medium and high speed bus and the high speed bus is not balanced - one side has half the level compared to the other side.
So there is a clue.
My next steps will be to unplug each ECU connected to the HS bus to see if the levels correct themselves (try to identify the culprit).
I did the same on a ford Fiesta 2013 and it seems to have good data on both bus's and they are well balanced so I now know what they should look like.

Does anyone have any experience with swapping ECU's from a donor car - do they work or do they get ignored as the wrong VIN?
I also did try another OBD2 scanner and it also could not connect (works on other cars).
The Nano also works on a D2 so it seems fine (you need to swap the OBD2 lead from VC4 to the blue one).
Funny - the car will start and show all the faults on the dash and message centre so son bus activity is happening.

Will keep digging and hopefully solve it and will post the journey so it may help some other owner
Denisrangie
PS - I am tempted to fix the D2 so I still can get out there.

Originally Posted by Denisrangie

Yes - we had a couple of ground issues - this thing has grounds everywhere.
I put a scope on both the medium and high speed bus and the high speed bus is not balanced - one side has half the level compared to the other side.
So there is a clue.
My next steps will be to unplug each ECU connected to the HS bus to see if the levels correct themselves (try to identify the culprit).
I did the same on a ford Fiesta 2013 and it seems to have good data on both bus's and they are well balanced so I now know what they should look like.

Does anyone have any experience with swapping ECU's from a donor car - do they work or do they get ignored as the wrong VIN?
..............................

I swapped the EAS (Electronic Air Suspension) module on mine with a new one from England, and it had to be reprogrammed using the VIN.

IIRC the earths to look at on a D3/4 are near the battery box, and there is a T-type connection under the front passenger door sill.

Try swapping the transfer case module because in D3s and D4s it is a HS gateway that isolates the main modules from the less important modules and it doesn't need reprogramming.

it's now at the point the engine will not run either - like a spreading cancer.
Mechanically the car is perfect.
I am going to park it for a few weeks to get it out of my head.
I have a good DF2 auto with the V8 so I am going to register that so I can get my off road hit over Xmas.
It need a bulb and wipers and a good detail and it is ready for rego.
Plan C would be a good D1 I also have (V8) manual - very reliable but needs a respray and a bit more with.
Both of these have way less computers to deal with.
I was toying with the idea of a new Defender (84 computers) but this whole D3 episode has me thinking - (NO WAY)

Why Vin Lock everything so you can't just swap the ECU's - 4 different data busses - is this really needed!
I had a good P38 that I crossed the Simpson in - the battery went flat and I did not use the car for a few months - The BCU refused to cooperate and would not allow new keys even with the software tool - so another Land Rover killed off by computer issues.
I can see why some are attracted to older Defenders - may be a truck and handle poorly but at least they seem to keep going.
Denisrangie