What's coded. What's not.

[Dieseldonkey]

Hoping someone can explain this with knowledge of what coding actually is and can explain to a lesser mortal like me how it works.

My understanding is that things like control modules are coded to the main ECU. The coding simply tells the ECU that the module is there and its functions.

Do any attached components then also have to be coded. For example airbag module is coded to ECU but the airbags themselves don't get coded to the module.

Saw another post where someone stated if the battery was replaced it needs to be coded to the vehicle. Couldn't get my head round that. It's an electrical component without any electronics. Is this correct?

 

[Loz]

Every module is coded to some degree, in most cases it tells the module what's attached and what options are available etc.

The Battery coding was not coding but Adaption, there is a module attached to the battery negative that monitors the amount of charge and drain. When you change the battery the module has to be told about the new battery and its capacity etc through a process called adaption.

 

[Dieseldonkey]

Thanks Loz. When you say module, are you referring to the actual component itself ie airbag, wiper motor, fuel pump. Or is the module part just the box of tricks that controls and interfaces with the likes of those components I've mentioned?

On a second note, would installing a leisure battery and a CTEK 250SA charger require any software update to the unit on the negative side once the secondary system is hardwired in?

Thanks again for your input.

 

[Pauly]

This is a great question and im sure there are plenty of people wondering the same

I think you misunderstand the term coding if you read it as programming not coding it is easier
Coding a module is telling that particular module how to behave, you are setting its functions and telling it what you want it to do (these functions are really preset into it and you are just turning features on and off)

Although all the modules can see each other and share info/communicate etc coding one module has no effect on other modules as you are not coding them together you are only commanding the single module to perform a function, now dont get me wrong if one modules goes south/loses communication this will impact all modules as the network (canbus) will sense a problem and multiple items will react to it.

The hub of the canbus data network is a module referred to as the Canbus gateway, this module is a bit like the master module and basically holds a list of all installed modules in a vehicle and allows them to talk to each other
When we are retrofitting something (ie adding a module that was not previously present) it needs to be connected to the canbus network, the module needs to be coded so it knows what its functions/limitations etc are then the can gateway has to be told the module is present to allow it and the rest of the network to communicate with each other

Lets look at an example, adding LED headlights, this retro fit has various stages but requires a new module to be installed that controls the levelling of the headlights
Lets skip past the actual installation and wiring of anything and assume the module has just been connected, as soon as the module is connected to the van and coded (programmed) with the correct data the module will function and the LEDs will self level when you fire the van up as they should, now the can gateway does not know this module is there so the rest of the canbus (network) cant not see it or talk to it so it will operate on its own.
LED headlights have a continental driving setting that comes up on the MFD menu to auto adjust for LHD countries now this is not present because the dash module does not see the levelling module !
This is where the can gateway comes in, we log into the gateway module and tell it the levelling module is present which announces it to the network and all the other modules can then see it and communicate with it and now it is available on the network we will see the extra entry in the MFD to set the headlights for LHD/RHD.
We only code the levelling module but the network responds to it appropriately and this can then have a knock on with other systems

I think i may have gone a bit further than your original question but that covers the basics of it i think, if you want to go further feel free to ask away

Going back to your original point about coding them together this is not really how it works, with a couple of exceptions you can replace a module and as long as the coding is correct on the replacement module the van wouldnt know/care and everything will continue to function fine. Obviously things like the radio and immobiliser are unique to vehicles and cannot be changed without dealer level hardware but the rest of it is must more generic

 

[Dieseldonkey]

@Pauly . Brilliant mate. Superb description and example. Your right, changing the term 'coding' to 'programming' gives a better understanding.

Is each module specifically designed to control a specific system. ie only an LED module can be used to control LED headlights. Or are they generic modules, just coded differently depending on what its driving. So for example could the same module used for LED headlights be recoded to control electric windows say. Assuming it's wired into that circuit of course.

 

[Pauly]

Every module is unique and only performs its intended function ie a levelling module can only do levelling, a door module can only do doors, each module type looks different/is a different shape and has a different amount of connectors on it etc
Some modules are common across platforms ie a module from a T6 could also be found in a Golf 7/Passat 8 etc things of the same era

Heres some random google images, the bottom one is a BCM the main brain of the van and is much larger than the rest

 

[Dieseldonkey]

Thanks again @Loz and @Pauly. Very informative read this evening and it's given me a better understanding of how all
the little silicon fairies that live in those black boxes are all interlinked.

 

[Loz]

Here is some more bedtime reading.

 

[former member]

Bring back carburettors and burn ECUs with fire!

Actually maybe don’t.

 

[Dieseldonkey]

Carburettor? On a diesel? Best of luck with that.

 

[former member]

Carburettor? On a diesel? Best of luck with that.

Well burn diesels too with their pesky “aren’t allowed to drive short distances” nonsense...

 

[DaveyB]

This is a great question and im sure there are plenty of people wondering the same

I think you misunderstand the term coding if you read it as programming not coding it is easier
Coding a module is telling that particular module how to behave, you are setting its functions and telling it what you want it to do (these functions are really preset into it and you are just turning features on and off)

Although all the modules can see each other and share info/communicate etc coding one module has no effect on other modules as you are not coding them together you are only commanding the single module to perform a function, now dont get me wrong if one modules goes south/loses communication this will impact all modules as the network (canbus) will sense a problem and multiple items will react to it.

The hub of the canbus data network is a module referred to as the Canbus gateway, this module is a bit like the master module and basically holds a list of all installed modules in a vehicle and allows them to talk to each other
When we are retrofitting something (ie adding a module that was not previously present) it needs to be connected to the canbus network, the module needs to be coded so it knows what its functions/limitations etc are then the can gateway has to be told the module is present to allow it and the rest of the network to communicate with each other

Lets look at an example, adding LED headlights, this retro fit has various stages but requires a new module to be installed that controls the levelling of the headlights
Lets skip past the actual installation and wiring of anything and assume the module has just been connected, as soon as the module is connected to the van and coded (programmed) with the correct data the module will function and the LEDs will self level when you fire the van up as they should, now the can gateway does not know this module is there so the rest of the canbus (network) cant not see it or talk to it so it will operate on its own.
LED headlights have a continental driving setting that comes up on the MFD menu to auto adjust for LHD countries now this is not present because the dash module does not see the levelling module !
This is where the can gateway comes in, we log into the gateway module and tell it the levelling module is present which announces it to the network and all the other modules can then see it and communicate with it and now it is available on the network we will see the extra entry in the MFD to set the headlights for LHD/RHD.
We only code the levelling module but the network responds to it appropriately and this can then have a knock on with other systems

I think i may have gone a bit further than your original question but that covers the basics of it i think, if you want to go further feel free to ask away

Going back to your original point about coding them together this is not really how it works, with a couple of exceptions you can replace a module and as long as the coding is correct on the replacement module the van wouldnt know/care and everything will continue to function fine. Obviously things like the radio and immobiliser are unique to vehicles and cannot be changed without dealer level hardware but the rest of it is must more generic

Great bit of descriptive work there @Pauly, bet that has helped out loads of folk, who were wondering what the dark art was all about.

 

[Tourershine]

I will admit, I was one of the folk that only semi-understood the terms and how they actually made things work, so thanks for this thread, it helps a great deal with understanding. One wonders if it's not a deliberate complication that only a few really understand, to justify the hourly rate the dealers charge when they diagnose faults 'out' of warranty, and us laypersons got told the justification for these charges are the £100's of thousands of pounds of equipment a dealer has to invest in to find and fix these issues. When in reality many non dealerships are just as capable of fixing issues with modern vehicles.

On that subject, my neighbour has a 5 year old Audi A6 Quattro that has just had a gearbox light come up, and an instruction to take to the nearest Audi dealership. Although he isn't short of a bob or two, he is a little concerned because they have told him that only they can find and fix the issue. Insinuating that other none dealerships won't have the diagnostic equipment to find and rectify the problem. I suspect this is a common problem with newer vehicles, and most people just trust that because of the complexity of modern systems, that it's always a main dealer fix, unless it's something more mundane like a set of tyres, or an MOT, hence the slow demise of smaller businesses, and the fast rise of bigger and more visually impressive looking main dealers.
I'm not against main dealers at all, and they do serve a vital purpose, but with hourly rates that vary so vastly, it's a very expensive option for some jobs. I'm not sure what VW's hourly rate is, but my BMW dealer charged me £120 plus VAT an hour and that was a couple of years ago last time I used them.

 

[former member]

It’s not Tiptronic is it?

 

[Tourershine]

It’s not Tiptronic is it?

Yup.
Ironically he took it out this morning and all his dash lights came on, so he's come home and it's literally just been collected by a recovery truck.

 

[former member]

Our BMW dealer is expensive but they are really good so I don’t mind paying.

But the nearest VW dealer is utter turd so I get a little miffed and generally drive 1.5 hours to the next nearest one where we bought the Cali from.

 

[former member]

Yup

Uh oh...

 

[Mooncat]

Carburettor? On a diesel? Best of luck with that.

It would never work!

Carbureted compression ignition model engine - Wikipedia

 

[Dieseldonkey]

Ah, takes me back to my days as a bairn fetling with needle valves on those things.

Place your bets now as to how many lights would appear on your instrument panel within 10 seconds of starting your T6 on
"....a mixture of kerosene, ethanol, ether, castor oil or vegetable oil."

 

[4motion]

I will admit, I was one of the folk that only semi-understood the terms and how they actually made things work, so thanks for this thread, it helps a great deal with understanding. One wonders if it's not a deliberate complication that only a few really understand, to justify the hourly rate the dealers charge when they diagnose faults 'out' of warranty, and us laypersons got told the justification for these charges are the £100's of thousands of pounds of equipment a dealer has to invest in to find and fix these issues. When in reality many non dealerships are just as capable of fixing issues with modern vehicles.

On that subject, my neighbour has a 5 year old Audi A6 Quattro that has just had a gearbox light come up, and an instruction to take to the nearest Audi dealership. Although he isn't short of a bob or two, he is a little concerned because they have told him that only they can find and fix the issue. Insinuating that other none dealerships won't have the diagnostic equipment to find and rectify the problem. I suspect this is a common problem with newer vehicles, and most people just trust that because of the complexity of modern systems, that it's always a main dealer fix, unless it's something more mundane like a set of tyres, or an MOT, hence the slow demise of smaller businesses, and the fast rise of bigger and more visually impressive looking main dealers.
I'm not against main dealers at all, and they do serve a vital purpose, but with hourly rates that vary so vastly, it's a very expensive option for some jobs. I'm not sure what VW's hourly rate is, but my BMW dealer charged me £120 plus VAT an hour and that was a couple of years ago last time I used them.

As the car is 5 years old I would have thought an independent audi or gearbox specialist would be able to cure it? VCDS software will do almost everything the dealer can do especially on a car of that age. Todays cars may be complex but in a few years time they will be out of the main dealer network and independents will have learnt what goes wrong and how to fix.

I like the way the main dealer told your neighbour 'only they could fix it'. It is main dealers arrogance that drives me from them, my local Land Rover dealer would take top prize for that, I feel quite out of place in their posh service department. Local VW car dealer is much the same as is Nissan dealer. By contrast my vw van centre is much better.