L322 Engine ECU query

So it turns out the engine ECU in my '03 L322 TD6 has decided to keep forgetting who the immobiliser module is. The diagnosis is that the engine ECU is at fault, and replacement is apparently imminent. My question is, is a used ECU able to be fitted and re whatevered to work with my engine?
My mechanic has the gear to do that unless, he says, the ECU's are coded with the VIN of the original vehicle(apparently a one time factory setting).
The reason for hoping to go used rather than new is the prohibitive price of a new one...$4500 - $5000 NZD...what the...
Any help hugely appreciated.

Axis said:

So it turns out the engine ECU in my '03 L322 TD6 has decided to keep forgetting who the immobiliser module is. The diagnosis is that the engine ECU is at fault, and replacement is apparently imminent. My question is, is a used ECU able to be fitted and re whatevered to work with my engine?
My mechanic has the gear to do that unless, he says, the ECU's are coded with the VIN of the original vehicle(apparently a one time factory setting).
The reason for hoping to go used rather than new is the prohibitive price of a new one...$4500 - $5000 NZD...what the...
Any help hugely appreciated.

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Wow, what's the price of another vehicle??
A good couple of things to check before you carry on are the battery is in top condition and that earth points around the car are not rusted and are not causing issues with the electronics on the car. A good culprit is under the front wings, a large earth point that rusts due to trapped humidity. It may be an issue causing yours
Other than that I'm not sure about the ecu programming, sorry.

I know...one of the perks of living in the deep dark south.
Will check the rust situation, earth etc, the battery is less than a year old, so should be good.
But can a used ECU be fitted and made to work with a different engine?
Sorry mate, just saw the last line in your reply.
All good.

Axis said:

I know...one of the perks of living in the deep dark south.
Will check the rust situation, earth etc, the battery is less than a year old, so should be good.
But can a used ECU be fitted and made to work with a different engine?
Sorry mate, just saw the last line in your reply.
All good.

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I'm not sure, sorry kiddo.
@Saint.V8 could shed some light for us

Axis said:

I know...one of the perks of living in the deep dark south.
Will check the rust situation, earth etc, the battery is less than a year old, so should be good.
But can a used ECU be fitted and made to work with a different engine?
Sorry mate, just saw the last line in your reply.
All good.

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Just because the battery is only a year old does not mean it's any good. Often an undersized battery is fitted leading to excessive volt drop when cranking. Need to check the voltage of the battery after it has stood overnight.
As Mark says, check all earth points and the battery connections.

Datatek said:

Just because the battery is only a year old does not mean it's any good. Often an undersized battery is fitted leading to excessive volt drop when cranking. Need to check the voltage of the battery after it has stood overnight.
As Mark says, check all earth points and the battery connections.

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Have spoken with the bloke workin on it and he assures me all of the above has been thoroughly checked and rechecked, and I’m inclined to believe him
What I really want to find out is whether or not a used ecu can be fitted and persuaded to work…a used one is around $200-$300, while new is $4000 - $5000, so yeh…NZD that is.
Although logically, why would secondhand ones be for sale if they can’t be used again, I’m thinking…or is that too simplistic of me?

Axis said:

Have spoken with the bloke workin on it and he assures me all of the above has been thoroughly checked and rechecked, and I’m inclined to believe him
What I really want to find out is whether or not a used ecu can be fitted and persuaded to work…a used one is around $200-$300, while new is $4000 - $5000, so yeh…NZD that is.
Although logically, why would secondhand ones be for sale if they can’t be used again, I’m thinking…or is that too simplistic of me?

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Can your bloke test the CCA of the battery. Having 12.6v doesn't mean the punch in the battery is big enough but if your sure and he's sure then fair enough. What size is the battery by chance can you remember?

I actually got the best one I could lay my hands on, can’t remember exact specs, but do remember going for max cca recommended. And forking out accordingly…
I know a dodgy battery can be the root of many evils, so yeah, wanted to get that bit right.

If it helps a quick google brings this from another site.

For a 2005 Range Rover if you swap the engine ECU with a used one it sounds like you have two options:
1.) Pay the dealer to reprogram the computer.
2.) Buy a used ECU with the matching key.

My question is do you also need the immobilizer, ignition/tumbler, and the door key lock?

Appreciate any assistance!

I'll answer my own question, you need the ECU, immobilizer, and key from the same vehicle. A nice to have is the door lock from the same vehicle to match the key. It appears as though you still need to have someone with a capable scanner clear the adaptation codes though.

Someone else comes back with

Reprogramming isn't needed, just resyncing the Immobilizer code to the 'new' ECU, but you would probably be on the hook for the same labor charge.

But yes, it would be Immobilization ECU, ECM, and key(the chip could be swapped from 'new' key to old key to retain the same ignition, glove box and ignition lock cylinders)

Cheers for that mate, I did search for this problem but kept comin to a dead end…Think I’ll give it a crack, at this point I have nothing to lose really.

Axis said:

Cheers for that mate, I did search for this problem but kept comin to a dead end…Think I’ll give it a crack, at this point I have nothing to lose really.

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Please don't forget to update us. Looks like one of them things we don't come across very often so a conclusion would be good.

backinblack said:

Please don't forget to update us. Looks like one of them things we don't come across very often so a conclusion would be good.

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Definitely will…funnily enough, that’s exactly what the mech tech told me. Wasn’t what I wanted to hear, but here we are

The EWS ECU (Immobiliser) checks the key code is correct and if it matches, it sends an 'OK to Start' signal to the Engine ECU. The Engine ECU then checks the EWS ECU to make sure it is the the right checksum value and proceeds to start the car...

If you swap the ECU, you have to get it matched to the EWS ECU and etc...sorry!

Interesting…thanks for that mate.
Since delving into this I’ve had so many conflicting answers.
And then this….
The local LR dealer boss of the workshop bloke told me today that the “official” answer according to Land Rover is as you say, that no, it can’t be done. But then he went on to say that actually, unofficially, it can quite easily be done, having the right gear. And of course his tech fullas have got the right gear.
SO…I’m gonna go and see these guys tomorra. Get them to spell it out for me.
Oh, and got the actual price of a new ecu from them too.
Get this. $4495 + 15 %GST.
Total: 5,169.25 NZD.
And thanks all for your help here. Good to know I’m not the only one tryin to understand these ridiculously comfortable unreliable cars…
Will update once I know more, for those interested.

Bit of an update, have found a place in the UK that will take my ECU and transfer the data from it to a "virgin" (their words) one. Essentially a used/refurbished/reset one. Same DDE numbers, which is apparently the important bit. And part number of course. Then it's plug n play upon return.
All for around $500 NZ...which is a number I can deal with.
Will update again when it's in the vehicle, a few weeks i reckon, by the time it gets there n back.

All sounds a bit too easy when I read it back to myself......fingers crossed though yeh?

Hopefully some good news then

backinblack said:

Hopefully some good news then

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It's like waiting for Christmas isn't it.fingers crossed

tomcat59alan said:

It's like waiting for Christmas isn't it.fingers crossed

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I'll will be Christmas before the poor chap get's it sorted

Latest update…sent ecu for swap and data transfer, installed it, no start.
Got mechanic to plug his magic box into it, exactly the same error. P1602, Engine ecu and immobiliser module comms fail.
Ah well, on the bright side, which I know most RR owners are familiar with looking for, it’s pretty much ruled out the engine ecu…
And so deeper we go…

Axis said:

Latest update…sent ecu for swap and data transfer, installed it, no start.
Got mechanic to plug his magic box into it, exactly the same error. P1602, Engine ecu and immobiliser module comms fail.
Ah well, on the bright side, which I know most RR owners are familiar with looking for, it’s pretty much ruled out the engine ecu…
And so deeper we go…

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I'd of thought your ecu would have been tested first?
Were the earth's checked around the car? Even the one under the front right wheel arch?