ECU lifespan?

Discussion in 'Gen 2 Prius Technical Discussion' started by landspeed, Apr 10, 2021.

  1. landspeed

    landspeed Active Member

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    Our ECUs are flashable, to allow fixes to be applied. The number of ECUs in our Gen 2 Priuses is reasonably substantial, and most of them are ‘required’ for function - if one dies, you need to replace it.

    The software in the ECUs is inaccessible. There are ‘calibration files’ which can be used in Techstream; these are encrypted, and they are installed as an update to the ECU by connecting to the CAN network via the ‘OBD2’ port, with Techstream. The ECU being updated then decrypts the ‘calibration file’ using an internal key that we most likely don’t know.

    While Toyota ‘calibration files’ for reflashing ECUs are of help for us to apply fixes, they only work when the ECU in question has an older version of the software - the ECU has to ‘authorise’ the software update before it accepts it. If we update our ECU, we can’t use the same calibration file to ‘reflash’ the ECU to the same version at any time in the future.

    Many ECUs don’t even have any updates released; an example is the NWH20 battery ECU. So unless we can ‘back up’ the software from that ECU, we can’t ever restore it.

    This link : https://www.samsung.com/semiconductor/global.semi/file/resource/2019/01/Memory_Solution_for_Automotive_180817.pdf

    is Samsung’s advert for automotive flash memory. It shows how it’s products will last 10 years (versus a 3 year warranty).

    All it takes is a single bit flip in an ECU’s flash ram to render our car useless.

    This issue is relevant to all cars that have flashable ECUs.

    The current situation is that, if a bit flip happens, the ECU will be checked by a technician, who will say ‘oh the ECU is broken’ and quote an obscene price for a replacement. And after statutory timeframes pass, they could say ‘oh the ECU is broken’ and ‘oh we can’t get those anymore’.

    Would anyone be interested in backing up ECUs so that when we face the above scenarios - we can reflash our ECUs (the microcontrollers have a ‘full reflash’ mode which lets you write anything to the ECU).

    I think we need a library, otherwise our cars will become museum objects far too soon (while cars with carburettors will keep on rolling).....

    Maybe the ‘right to repair’ movement could help us here?
     
    SFO, Diemaster, Mendel Leisk and 2 others like this.
  2. meeder

    meeder Active Member

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    ECU's do die but we have had cars on the road with multiple ECU's for well over 30 years.
    I don't think that the failure rate is very high.

    I do agree that a backup of the software should be made possible.
     
  3. landspeed

    landspeed Active Member

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    It is true - but as an example, the Nissan 200SX has ECU ‘chipping’ by replacing the mask ROM - the advent of flash ‘ROM’ is recent enough that we haven’t seen the failures yet (it is lasting longer than the 10 years in that Samsung advert); it still feels like planned obselence!
     
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    For any given model, a substantial quantity have come off the road for failures other than the ECU. A fair number of them were properly dismantled and the ECUs filed away on a bulk shelf.

    It's likely that the dedicated Prius long span operator can simply consume those resources instead.

    That said, I support the idea of making backups. I'm equipped with a Tactrix interface and a skill or three. Let me know if there's anything I can test?
     
  5. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    The last time I looked up the price of an ECU for a car the price was something like $30 with the standard 90 day guarantee.
    As stated above, there are warehouses full of G2 parts available out in the world and I’m thinking that the ultra low failure rate is keeping the prices for these units reasonable.....

    .....unless of course you choose to go to the dealer for a replacement, which I suspect would be about 2-3 times what they charge for a “throttle body cleaning” or “A/C refresherizer treatment.”
     
  6. PriusCamper

    PriusCamper Senior Member

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    For the reasons stated above, and also for proprietary control, I've never seen any Prius DIY ECU flashing... I'm a member of MHH AUTO and they're all about hacking & flashing vehicle computers, but not for Prius.

    It's sad that Toyota still lives in a cave inside a walled garden when it comes to computer code. If they open-sourced / crowd source our ability to re-code and re-flash the innovations that people would come up with would be incredible.

    I long ago had an Archos Mp3 player that was open-sourced and a huge group of people worked on upgrading the firmware in so many ways you could even play video games on the device. Best of all, they eliminated all the known problems with the original firmware. It's a great way for a company to innovate without spending any money and as long as there's enough innovators, there's enough checks and balance to keep it safe. But Toyota's business model is to get you to buy the newest model of car, not improve the functionality of their older cars, so...
     
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  7. landspeed

    landspeed Active Member

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    What brought this up was that I had thought about it a few years back, and had started writing a V850 simulator. I will revisit this at some stage! However... my car stereo had a 1GB SD card that came with it (2nd hand Blaupunkt Memphis MP66, still great sound), and the songs died one by one. I reformatted the card and have been playing my music ever since. While the card is undoubtedly of a lower quality than automotive flash, it still shows how the data ‘decayed’ over the years (I used aux-in so ignored the card much of the time). The flash software in our ECUs is literally charged electrons sitting in little pits; if enough electrons leak away, a 1 changes to a 0;

    there is a leak of a Toyota Tacoma ECU file I have, but I wish I had the battery ECU as well as others. Amusingly the Nissan Leaf BMU has a chip that is fully documented with user manual; but the ROM is not able to be read. *but* there are companies that can reprogram the ROM with new features so someone *did* manage to get the ROM! (the same V850 / NEC / Renesas chips are using even in the Leaf, although multi core and higher clock speeds are a thing now!
     
  8. Diemaster

    Diemaster Active Member

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    There SHOULD be a way to connect a device, say a bus pirate, and at minimum, do a dump-to-file to get the exact contents of the rom/flash out. I had a ex-co-worker do this to save / archive old arcade game Roms so a japanese company could "keep them alive" making software emulators. This could be called a "backup" of sorts. We could attempt to de-compile the source code then too. depending on the size, you could be taking several hundred thousand lines of code. One comma instead of period would screw it up.
     
    #8 Diemaster, Apr 12, 2021
    Last edited: Apr 12, 2021
    landspeed likes this.
  9. PriusCamper

    PriusCamper Senior Member

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    People who build apps sniff the CAN bus for codes... But nothing comprehensive like what happened with Honda and Subaru mods
     
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  10. landspeed

    landspeed Active Member

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    The NEC / Renesas chips have a bit you can set that says ‘you can’t read this flash rom’ - someone said Yoshi (SuperMID) did this; I never tried to read the ROM, but used two SuperMIDs in my 1980s turbocharged Nissan’s - is he still around? I haven’t seen him around for approximately a decade. He is a legend.

    I will go back and read the NEC / Renesas documents to see if ‘delete the whole flash if someone attempts to read’ is a thing....

    If that was a thing, the next stage is to see : can you activate the ‘burn it to the ground’ protocol, and then pull the power supply in an instant? That could allow someone to then write a short program that dumps the ROM over the CANbus and ‘install it’

    I worry this is a waste of time since other people have already found vulnerabilities; in New Zealand new petrol cars will be banned for import in 9 years (the ones on the road will obviously stay alive as classic cars). So I will have a Gen 1 Honda Insight, two CA18DET 200SXs, two CA18ET Bluebirds (U11, T72); CA20E U12 Bluebird, Honda CT110 ‘postie bike’, NWH20 Prius, and two NWH11 Priuses. Also a 2.7 litre Toyota Hiace 2010 Widebody, high-roof, super-long-wheelbase. Also a random 2010 Nissan Micra.

    I plan to buy a V10 BMW M5 or M6 ‘because’ (they are cheap in NZ because the routine service includes ‘rebuild the big ends’ and ‘replace the THANOS (not vanos) pump; I will also have a V12 Jaguar XJS before 2030 (fuel economy is actually OK if you baby the gas pedal over long distances); it will need e-bikes to avoid the horrific city MPGs...
     
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