Any logs anyone could send me from a Leaf would be great. But, I might be on to something. Byte 4 (the fifth byte if you start counting at 0) is always a constant value for a given car. It stays the same across all 0x5C0 frames, it stays the same whether driving or charging. Every vehicle I've got a capture from has a unique byte here that never changes with any captures from that car no matter what else the car is doing. Pretty much all of the rest of the bytes change as you charge or discharge. I think what might be happening is that this byte is a sort of identifier that the rest of the system uses to see whether the pack is the same one it last knew. 256 unique values might not seem like a lot but that means that your odds of getting a pack with the same byte as your old pack is 1/256 or less than 0.5% - not so likely. One way to test this would be to set up a man in the middle configuration and then change that byte and see if it makes the car puke. Or, take a car with a replaced pack and try to change the reported byte from the new LBC to the reported byte from the old LBC and see if the car then wants to work better.
It seems a little bit cheap that they'd use a single byte for validation but it's possible. So far as most anyone would be concerned a 1 in 256 chance of a new pack working might as well be one in a billion. If you needed to replace the pack in your car would you take a 1/256 chance that the pack you bought would work? And, assuming people did find out about the scheme for most people that'd mean having to stock hundreds of salvage packs in order for your customers to get a pack that works for their car. But, without further testing this is all just a guess. On Thu, Jan 26, 2017 at 7:03 PM, Chris Meier via EV <[email protected]> wrote: > I was told by the dealer that the shorting of the 12v leads is one of the > approved steps/workarounds in the TCU update. > > Afterwards the gauges were off until one drive/charge cycle. > -- > -Chris > > On January 26, 2017 12:29:37 PM CST, Cor van de Water via EV > <[email protected]> wrote: >>The Supercaps that you mentioned are present in every car with >>electrically operated brakes. I know of the supercap bank in the trunk >>of every Prius since pretty early on (I think the "Classic" 2001-2003 >>does not have it, but I am certain that since 2004 it is wht allows you >>to apply brakes a few times when suddenly the aux battery goes out >>while >>driving). >>I checked the wiring diagram and indeed there is a "Brake Power Supply >>Backup Unit (B15)" on the diagram. Typically those will *not* feed >>power >>back to 12V aux battery, so this should not be the reason a car behaves >>differently with a short or long disconnect of the aux battery. >>What might be the case is a capacitor on the memory of a computer that >>is designed to withstand a short disconnect, to allow you to change >>your >>battery without losing all your settings. >>Typically such a capacitor is not feeding back to the aux battery >>either, so in any case clicking the loose battery wires together should >>make very little difference in how long it takes for the car to behave >>differently. >> >>Also, the LBC validation happens without disconnecting the aux battery. >>I know for sure as I never disconnect the 12V battery and when I >>swapped >>my pack for a complete replacement pack from Washington State, the >>yellow light on the dash came on and my Leaf was in Limp mode while I >>only disconnected the (non-energized, due to the contactors in the >>pack) >>HV lines and the control bus. >>Just wheeling the original pack back under my Leaf and swapping the >>connectors removed the Limp mode, so I know for a fact that the Leaf >>validates the battery upon pressing the power button while the aux >>battery is connected continuously, so it seems that you were looking at >>the wrong thing. >>Probably a trace of the EV bus as soon as the power button is depressed >>(when a *lot* of communication is happening) will tell the story. >>You may start the trace as soon as the brake is pressed. >>Good luck! >> >>Cor van de Water >>Chief Scientist >>Proxim Wireless >> >>office +1 408 383 7626 Skype: cor_van_de_water >>XoIP +31 87 784 1130 private: cvandewater.info >> >>http://www.proxim.com >> >>This email message (including any attachments) contains confidential >>and >>proprietary information of Proxim Wireless Corporation. If you >>received >>this message in error, please delete it and notify the sender. Any >>unauthorized use, disclosure, distribution, or copying of any part of >>this message is prohibited. >> >> >>-----Original Message----- >>From: EV [mailto:[email protected]] On Behalf Of Collin Kidder >>via EV >>Sent: Thursday, January 26, 2017 8:02 AM >>To: Tom Parker; Electric Vehicle Discussion List >>Subject: Re: [EVDL] Anyone interested in 2015 Leaf drivetrain or >>interior/exterior/suspension parts? >> >>10 minutes should have been enough. Chris suggested shorting the >>positive and negative together to drain any capacitance and force the >>ECUs to reset but I cannot imagine an ECU lasting 10 minutes on its >>input capacitors. Though, I think that the leaf actually has a super >>capacitor behind the rear seats so it might take a long time to drain >>that off. It might be worth a try to make sure the 12v wiring is >>really, truly drained. I did some work with adding a secondary battery >>pack and initially made a number of bad mistakes that caused critical >>ECU faults. Disconnecting the battery for a few minutes would not >>allow me to clear the faults but disconnecting all day and trying it >>again the next day would work. I think eventually someone suggested >>shorting the battery terminals and doing that does allow for resets >>more quickly. Though, if I'm right about the super cap being for the >>12V power then you might want to discharge through a power resistor >>and not just click the terminals together. It doesn't hurt to use a >>resistor in either case. It's better for the car anyway. >> >>Otherwise, it does appear we're looking at a message that is more >>continuous. That doesn't mean that it necessarily happens quickly. On >>the Tesla Model S there is a series of messages that transmit the VIN >>number of the vehicle, presumably for authentication with various >>components. These messages are only sent something like every 5 >>minutes. So, they'll show up as messages that aren't necessarily one >>time and done but they've got a very long interval between >>transmission. If you have the means to check transmission interval you >>might try that. Actually, I have captures from various Leafs on the >>powertrain bus and I do have the means to check the interval so I'll >>check and see if I can find messages that maybe don't get transmitted >>so often. A validation message might only be every second or couple of >>seconds. There's no need to spam the bus with serial number validation >>every 10ms. Really, I didn't think there was any need to do it more >>than once but maybe it really does. This whole business of component >>validation is just plain annoying. Are chop shops really that big of a >>thing or are the automakers just that DIY hostile? >> >>On Thu, Jan 26, 2017 at 4:33 AM, Tom Parker via EV <[email protected]> >>wrote: >>> On 24/01/17 23:25, Tom Parker via EV wrote: >>> >>>> On my car, there is only one frame that isn't repeated continuously >>after >>>> startup (0x603 is sent once, with a single byte payload which is 00 >>in my >>>> captures). >>>> >>>> I'll try disconnecting the 12v battery tomorrow and see if anything >>>> different happens at when it's connected, or during the first >>startup. >>> >>> >>> I removed the 12V battery and there was no activity on the EV CAN bus >>when >>> it was reconnected. There were also no new messages when I turned the >>car >>> on, and other than 0x603, they all streamed continuously. I waited >>quite a >>> long time (10 minutes maybe) before reconnecting the battery. >>> >>> I guess this means the BMS authentication is in the repeating >>messages, or >>> it is triggered by some other event than disconnecting the 12V >>battery, or >>> you can have the 12V battery disconnected for a very long time >>without >>> breaking the BMS authentication. >>> >>> _______________________________________________ >>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>> Read EVAngel's EV News at http://evdl.org/evln/ >>> Please discuss EV drag racing at NEDRA >>(http://groups.yahoo.com/group/NEDRA) >>> >>_______________________________________________ >>UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>Read EVAngel's EV News at http://evdl.org/evln/ >>Please discuss EV drag racing at NEDRA >>(http://groups.yahoo.com/group/NEDRA) >> >>_______________________________________________ >>UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>Read EVAngel's EV News at http://evdl.org/evln/ >>Please discuss EV drag racing at NEDRA >>(http://groups.yahoo.com/group/NEDRA) > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
