Vida CEM swapping

[rkam]

Each controller will send information periodically and on events like pushing a button. Then other controllers will read this information if they are programmed to do so and need it. They must therefore understand each other.

[dikidera]

I understand that, but each controller should still somehow know which module is sending the data. This signal configuration is doing exactly that, but if it changes between software upgrades. I wonder what changes and why it isn't static and "hard" coded.

Anyway, I still wonder what those missing/additional components do in the CEM variants.

[rkam]

Yes. The problem is they can't ask each other how to communicate. They must already know. There are no master list in the car. Volvo knows centrally and can produce matching configuration files for all controllers. These will also contain information about what relevant information can be received from the other controllers. This includes CAN ID and how to understand the data bytes.

[dikidera]

So the algorithm for understanding them must be in the ROMs?

[vtl]

I do not plan to keep the old Denso system and just use Bosch. But then the entire engine harness needs to be replaced which would not be a serious problem if I am going to be removing my engine.

That's a bad idea. You still can do it, with help of Volvo hackers who know a lot about this platform and can stitch together modules and software that can make car to run.

But it is cheaper, easier and quicker to sell what you have and buy what you want. Better spend those extra money in bringing the new to you car to stage 0.

[vtl]

So the algorithm for understanding them must be in the ROMs?

It does not work like that. The developers write software for car modules in a very high level abstractions, like "AWD controller reads the engine speed". What CAN IDs they get, or whether it is CAN bus at all, materializes all the way down, near the turtles. The communication toolchain enumerates all the objects (controllers, sensors, counters in RAM, etc) present in the system and assigns them various IDs. In some cases it generates a bridged code for module A to access module B via module C, because there's no direct communication between A and B. All this "knowledge" is a part of software for the module. It knows how to talk and listen to modules it needs to talk and listen to, and nothing more.

Adding one more sensor to just one module may shift all the IDs in the system. That's what often makes adjacent model years incompatible in software, though the hardware is mostly or exactly the same.

Same toolchain generates data and their relation for tables in VIDA database.

[dikidera]

I do not plan to keep the old Denso system and just use Bosch. But then the entire engine harness needs to be replaced which would not be a serious problem if I am going to be removing my engine.

That's a bad idea. You still can do it, with help of Volvo hackers who know a lot about this platform and can stitch together modules and software that can make car to run.

But it is cheaper, easier and quicker to sell what you have and buy what you want. Better spend those extra money in bringing the new to you car to stage 0.

I am afraid it doesn't work like that over here at least where I am from. Price of cars skyrocketed and wages(which were not rising) were left in the dust after a year of inflation of probably double digits every month. A car previously costing the equivalent of 2000 dolars, is now 3500-4000 or higher. To summarize, I do not have the money to buy what I want, I only have enough to fix it with the current engine, maybe convert it to turbo for <$1000 or...part it and be left without a car for the next 5 years or so.
It is cheaper to DIY than to buy it. I also have nothing to sell, my bifuel model is with me to the grave, even if unintentionally as no one will buy it. Why? Well, CNG variant, which experienced the highest price per liter known to man, a fuel tank shy of 30l on petrol.

Anyway I am curious to know of your opinion why it's generally a bad idea like what you are specifically foreseeing. I have not extensively verified it, but what I could scavenge, the CEM is the same pin-wise, though I cannot verify the software difference side. And if need be I will replace the CEM with one from a Turbo variant and program the immobilizer stuff(as with the ECM) and the so-called linking between ECM and CEM. The electrical wiring specs https://www.manualslib.com/manual/53393 ... e=1#manual at the very least do not seem to present a big challenge, this statement is true until I actually face a challenge which cannot be overcome easily.

[vtl]

Fix the engine then. It is the cheapest. I followed a few conversions (one was as simple as 2.5T engine into MY01 car), it is a hell of a job, with crazy time and money budgets.

[dikidera]

Fix the engine then. It is the cheapest. I followed a few conversions (one was as simple as 2.5T engine into MY01 car), it is a hell of a job, with crazy time and money budgets.

I am very curious to know what the problems encountered were with said conversions?

Addendum:
And when I said cheaper, I still meant if I do it myself. My mechanic actually told me a while back to drive it as-is until it dies. He actually said it's not worth it to replace the engine, because we are talking about an entire overhaul(re-ringing, re-honing the block, polishing the crankshaft and maintenance on the head such as new valve seals etc).
I will know more as soon as I open the engine which will not be for a few more weeks. It all depends on the state of the current block.

[rkam]

I guess you would have to figure out how your Denso communicates with all the other controllers, and then make your Bosch do the same.

The format of the signal configurations and the available/needed data is going to be different. So it can not easily be moved over.

If you find an engine from a car that is otherwise identical to your car, and Volvo has decided to make that particular ECM software match the rest of your car, and not the other way around, then there could be a tiny chance.
TCM, SUM, BCM, ETM, DEM, CEM ... depending on what is in your car.