Nope ECM carries code BECM learns it. Swopping ECMs means the BECM has to learn the ECM code for each unit.
alarmfitter
New Member
he read the code on the ecu before removing it then when fitted to the other car he put the 4 digit code into the becm i hope that explains what needs to be done. 
eightinavee
Well-Known Member
I've been doing these swops loads of times since 2003,its the other way round.If the EDC held an unswappable code that the BECM had to learn you could put an edc ecu back into its original car after coding it to another and it would work straight away as the original car would know its original ecu - but it wont,it needs a relearn before it will go again,proving that the BECM holds the code which the edc has to learn.
Try it,stand 2 p38's together and swap edc's.
Tried to paste in a section of a factory SIDS,which explains it all,puter says no....
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eightinavee
Well-Known Member
No,for the last 9 years I have been using Testbook T1 and T4 to perform this operation with info direct from factory SIDS and using advice from LR dealer technical support.I have probably 5 P38 edc ecu's on the shelf with a similar number of Gems units.Plus probably 40 other LR ecu's from Mems to Slabs to Motronic.
Have you ever actually tried what I suggested between cars rather than coding ecu's to a single car ?
No, I haven't swapped EDC ECU's between cars - I only have one p38 thank god.
The experts in this are Blackbox Solutions. I am using a Faultmate MSV2 and the software is very straight forward to use. I am guided by their help files and I go on their forum which is also a good source of information.
The experts in this are Blackbox Solutions. I am using a Faultmate MSV2 and the software is very straight forward to use. I am guided by their help files and I go on their forum which is also a good source of information.
eightinavee
Well-Known Member
This is the difference,not so often now but i used to have 5 or 6 of the horrible things in my yard at once,mostly belonging to local garages who wanted them fixed for nothing.I had to quickly learn any shortcuts I could to earn money.If the edc ecu's held the code it would have meant not having to do a relearn on returning an ecu back to its original car - all of which took time.I'm not trying to be clever here - I'm just telling you what I had to do,in order to make them work.You do see my point about where the code is held ? Otherwise I could have chucked them straight back from whence they came and they would fire up.
Not having a go at you mate. I respect the experience you have.
Many years ago I was a vehicle mechanic in REME but not up todate with modern stuff.
Just trying to get to the bottom of how security sync works and the peculiarities of the different diagnostic systems.
Dave
Many years ago I was a vehicle mechanic in REME but not up todate with modern stuff.
Just trying to get to the bottom of how security sync works and the peculiarities of the different diagnostic systems.
Dave
Why then if the BECM holds the code, when car goes out of sync does the BECM hold a scrambled code and not the ECM. You have to go into ECM to read the code it holds and write it into the BECM. Once the ECM is set to robust it CANNOT be changed back to none robust. The code it holds is active and CANNOT be changed. But the code in the BECM can. Security learn just reads the code in the ECM and writes it to the BECM. That is what a syncmaster does as far as i am aware.
eightinavee
Well-Known Member
I cant answer that - I'm not an electronics specialist,but what I would say is that when you set an ecu to robust immobilisation in a Disco/defender with Testbook,all it means is that it needs a code - it wont just boot up without a code when fitted to any old car.Testbook does not ask for a choice of robust/non robust when programming a new BECM or engine ecu to a P38.
But if what you say is right,refitting an edc back to its original car after using it on say a faulty car - it should fire straight up.It wont,it needs a relearn,which is why it needs a relearn.
I'll try to find a diesel SIDS from my old E-mails from LR Tech and see if there is any more info there.
Don't know about the system on the Disco or Defender. I am talking the P38 fitted with the M51 engine. See what you can find out. In all the literature i can find and in practice it seems that the ECM holds the code and when robust the BECM requests that code, which has to match the code stored in the BECM for the engine to start. Otherwise the engine is disabled. BUT the code in the ECM cannot be changed and must be read and copied to the BECM in the initial set up. When the car goes out of sync the code in the BECM is lost or scrambled. To resync the code must be read from the ECM and written back to the BECM.
eightinavee
Well-Known Member
Cant find any diesel specific stuff in the SIDS,only BECM and Gems. Looking on Topix it shows you are right in as much as the code originates in the EDC ECU.And the robust/non robust setting changes from non robust to robust for the 96 model year.(I'd forgotten that,its been a long time...)
But what I still cant get past is that Testbook tells you that the engine ecu has to learn the code and will check to see if its learnt.Plus the main thing that an ecu needs a relearn back in its original car after being used in another one.....
Now I'm confused.
But what I still cant get past is that Testbook tells you that the engine ecu has to learn the code and will check to see if its learnt.Plus the main thing that an ecu needs a relearn back in its original car after being used in another one.....
Now I'm confused.
Yeah me too. Never used Testbook but it does seem to do some things arse about tit. Maybe the security learn is the BECM learning the ECM code, that's the way i see it. The code in the BECM can be changed by Nanocom and Faultmate. The one in the ECM can't.
Datatek
Well-Known Member
That is pretty much exactly what I have been told. The EDC code is fixed, the BECM sends the same code to the EDC which if it matches the fixed code held in the EDC the EDC then responds again with the same code back to the BECM. This only fails when the BECM code gets scrambled.
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Rick-the-Pick
Active Member
None of the engine management codes can be change. The settings in the becm have to be programmed to the ecu, except gems. The gems engine management has to be learnt to the becm, the same procedure applies to the disco's.
Non robust & robust modes can be changed as & when required.
Any edc engine management can fitted to the diesels, as long as the edc code is entered into the becm. Any motronic engine management can be fitted, again, as long as the codes are programmed into the becm.
Does this clear up any confusion?
Non robust & robust modes can be changed as & when required.
Any edc engine management can fitted to the diesels, as long as the edc code is entered into the becm. Any motronic engine management can be fitted, again, as long as the codes are programmed into the becm.
Does this clear up any confusion?
eightinavee
Well-Known Member
Nearly,but not quite ! First off why does an EDC need a relearn when it goes back to its original car after being used in a suspect car.Secondly Rick, the manual box variants of the EDC ecu's will run the engine,but not talk to the autobox.Auto ones work OK in a manual car.Guess which type of tranny is most common,and guess which type I have on the shelf......
But it's not the EDC that needs the re-learn it's the BECM. The code in the EDC stays the same, the code stored in the BECM changes to suit it.
