Yes I can't argue against what you are saying it is logical but the ECU writes a lot semi permanent data to somewhere , valve /pressure reg characteristics and auto adaption data, does it put this in flash? or maybe maintained ram I don't know. What I do know is that the Lexia doesn't tell me the things that I really want to know like what map has it elected to use and what sportivity index is it using as part of it's adaptive function so I have no way of knowing if things are logical or illogical apart from the fact that hanging on to second gear to 4k on a level road and trailing throttle is definetly pants.xantia_v6 wrote:cachaciero wrote:Firstly, I am sure the firmware in flash would be check summed and checked at boot-up, to detect a failed re-flashing.CitroJim wrote:
That.s what I am thinking. Without knowing just how much of the S/Ware is in hard rom and how much is in flash it is difficult to be sure of anything. However for sure the basic MAPS will be in flash.
The next thing is that flash memory is VERY stable and reliable once it has been written, I can't remember hearing of a random data corruption in flash (ignoring issues related to wear-out and the process of writing).
Wear-out of flash can be an issue, but that is related to the number of write cycles of a location (100,000s), and is unlikely to be an issue here, as software that writes data to flash uses wear-out avoidance techniques (and some chips perform this in hardware) to extend the life to millions of write cycles. In any case, if you have a flash wear-out problem in the data area, then re-flashing is not going to help.
It is possible that some data variable or counter that is stored in flash ha become corrupted, due to a power glitch while writing etc, but if the Lexia reset did not fix this, then re-flashing is not likely to either, because re-flashing probably doesn't overwrite the data areas of flash.
Can the C5 transmission ECUs be
swapped between cars, or are they one-time coded?
I am though not convinced that it does a memory checksum check before powering up because if any data is changing and I believe some does then it would have to do a checksum calc and write after every valid change and I have doubts whether the software is that professional.
cachaciero