Hello all!
Long time watcher, first time poster who finally needs to ask for your help/advice. I am warning you in advance, that I am a newbie who knows the basic theory and enjoys watching a lot of youtube videos of Mike, Dave, AvE, Jerri Elsworth, Applied science and so on, however, I am not by far an electronics engineer.
I have an automotive repair dilemma here which ultimately boils down to electronic fundamentals in repairing a water damaged device that processes CAN signals.
INTRO startskip this if you are not interested in the explanationsI own a volvo s80 (2003) that has stood on the outside for some time and it has turned out, that it has the infamous sunroof drain problem which in turn has caused water damage to the Central Electronic Module of the car. If anybody is interested in more details, please ask, but I arrived to this conclusion after a few basic fixes of the failed window washer pump did not work... And after taking out the module itself, you can see the substantial damage caused to it.
The repair at the dealer costs too much for me to consider this option - 1000 EUR for the module plus another approx. 200 EUR for adding it to the car as they apparently have unique identifiers and the ECU will not recognize it, thus it will not work (there is some blabber about downloads from Volvo servers within the VADIS (volvo's own diagnostic software) package which you need to have a subscription etc.) All of that being done to prevent these modules from being stolen and sold left and right.
I have googled quite a lot and it seems that these modules are easily repairable, and a few people have completed it, but with different main causes. As well as there are services that specialize in the repair of these devices.
INTRO endThis leads me to believe, that I can attempt a DIY fix for it. I have a donor device, but I am not sure of the internals as I haven't had the time to pry it open and see if they are similar internally.
The more interesting and detailed explanation can be found here:
http://lag.lt/repairing-volvo-cem/A Lithuanian guy (I am Latvian) has replaced the MCU from a donor device in to his old device and it has worked.
A picture of the old and new devices from the blog for those who do not surf links:
Due to the fact that my CEM module is badly damaged, I do not think that a lot of the components will be usable as the water has corroded a lot of pins which have come out, as well as surely corroded much more.
This leaves me with the option, that is being stipulated in the blog above:
"
read flash from dead CEM; re-program new replacement CEM, done."
in your, experienced opinion - is this a feasible option? would it be possible with simple tools to pull the the data from the flash (I assume this is what stores the ID and other config data that is being transmitted to the ECU so that it gets recognized/becomes compatible) or is there a caveat that neither the author of the idea, nor me do not see? (something along the lines of the fake FTDI chips and them being broken if you use official software?).
why does the author say, that he has tried swapping the flash chips around and it did not work? due to different hardware layouts maybe?
As well, I assume that the replacement/donor module, that I have acquired, has to be 1:1 to be compatible with the car itself (i do not expect an answer to this).
Please see a gallery of the water damage to my module below:
http://imgur.com/a/wGSNfI would really appreciate any input in this as going down the expensive route is not really something I want.
Thanks,
Juris.