3 ms·

You are right but at the same time one does not expect a component of the dashboard to actually brick a car. I guess.

zrobotics 7y ago
While counter-intuitive, I have actually encountered this issue with other cars as well, specifically a Ford f150 where an internal problem in the APIM module (accessory protocol interface module, essentially the dash touchscreen controller) essentially bricked the truck by spamming the canbus with erroneous signals. Remember that modern automobiles are rolling networks with multiple interconnected controllers, some of which are required for the vehicle to function. Note that this doesn't excuse Tesla here, since the situation I discussed is very rare, normally if that module fails the vehicle will still start and run. Tesla engineers should absolutely have been aware of this issue, as pointed out up thread there are multiple tutorials for ras-pi SD memory preservation, and I have trouble believing a competent EE shouldn't be aware of life issues due to eMMC. It also shouldn't brick the car, normally automotive electronics are designed very carefully to avoid single points if failure, with fallback routines and safety "limp-home" modes in case of problems.
- pvg 7y ago
  bricked the truck by spamming the canbus with erroneous signals. Wasn't preventing this one of the design goals/selling points of CAN?
  - zrobotics 7y ago
    Yes, that is one of the strong points of CANBUS. Like I said in the original post, this was a very rare failure. However, the APIM managed to spam the bus in just the right way where it de-synced modules; when I initially connected to the vehicle w/ a snap-on scan tool it was throwing codes for BCM and TCM non-comm, as well as codes that implied the ECM was seeing different speeds on the CKP & CMP (crankshaft & camshaft sensors). The CKP/CMP disagreement was what caused the vehicle to be 'bricked', since the engine management had no idea where the crankshaft & valves were in relation to each other. Near as I could tell from my scope, the APIM was spamming the bus with exactly the right frequency to interrupt the ECM during it's scan of critical sensors. It was an extremely rare failure, and to Ford's credit they covered both the repair as well as my shop's diagnostic time. edit: To make it clear, I have seen 2 vehicles that still operated with a direct CANBUS short to ground, as well as a vehicle that had CANBUS shorted to 12V+. In these cases, aside from expected failures (such as the BCM systems not responding, or transmission limp-home), modules were able to fall back into either safe states (limp-home, in the case of the TCM) or just a dashboard warning light (in the case of BCM no-comms).
- pfortuny 7y ago
  Wow! Unbelievable. I mean, just SEPARATION. Thanks for the anecdote!
deleted 7y ago
[deleted]
zaroth 7y ago
“Bricked” is supposed to mean “permanently and unfixably ceasing to function”. That’s absolutely not what is happening here. The article is completely and inexcusably wrong on this point. The car won’t run when the eMMC chip fails, and Tesla solution is a new MCU board which costs $2,700 out of warranty. Not surprisingly Tesla is not desoldering and reworking just the eMMC chip. There are any number of components that can disable a car, from the battery to the starter to something with the ignition, electronics, anti-theft, etc. Sometimes the repair is as simple as a new battery, sometimes the repair is an expensive piece of hardware.
- EpicEng 7y ago
  Yet those things are crucial to the fundamental operation of the vehicle. We're talking about logs no user cares about here. It's just sloppy and a silly failure mode.
  - zaroth 7y ago
    Anti-theft is not crucial to the operation of the vehicle, and that had certainly immobilized plenty of vehicles, sometimes in expensive to fix manors. Now if the article was that Tesla Model S has a chip which wears out and the board holding the chip is expensive to replace, and maybe even getting into why don’t they push a software update to lower the writes to that chip — I would not disagree. The article falsely claimed the cars are “bricked”. As it’s the main thrust of the article, it should be retracted. > However, until the company starts stocking parts like the eMMC chip, as well as release detailed service manuals to the public, Tesla is going to be looking at a number of newish cars dead in a junkyard real soon. They should stock a chip which is soldered to the board, and what, do reworks? That’s asinine. Newish cars dead in a junkyard? Totally false. It’s an expensive repair for a problem that could have been avoided, and hopefully Tesla will remedy with a firmware update.

While counter-intuitive, I have actually encountered this issue with other cars as well, specifically a Ford f150 where an internal problem in the APIM module (accessory protocol interface module, essentially the dash touchscreen controller) essentially bricked the truck by spamming the canbus with erroneous signals. Remember that modern automobiles are rolling networks with multiple interconnected controllers, some of which are required for the vehicle to function. Note that this doesn't excuse Tesla here, since the situation I discussed is very rare, normally if that module fails the vehicle will still start and run. Tesla engineers should absolutely have been aware of this issue, as pointed out up thread there are multiple tutorials for ras-pi SD memory preservation, and I have trouble believing a competent EE shouldn't be aware of life issues due to eMMC. It also shouldn't brick the car, normally automotive electronics are designed very carefully to avoid single points if failure, with fallback routines and safety "limp-home" modes in case of problems.

pvg 7y ago
bricked the truck by spamming the canbus with erroneous signals. Wasn't preventing this one of the design goals/selling points of CAN?
- zrobotics 7y ago
  Yes, that is one of the strong points of CANBUS. Like I said in the original post, this was a very rare failure. However, the APIM managed to spam the bus in just the right way where it de-synced modules; when I initially connected to the vehicle w/ a snap-on scan tool it was throwing codes for BCM and TCM non-comm, as well as codes that implied the ECM was seeing different speeds on the CKP & CMP (crankshaft & camshaft sensors). The CKP/CMP disagreement was what caused the vehicle to be 'bricked', since the engine management had no idea where the crankshaft & valves were in relation to each other. Near as I could tell from my scope, the APIM was spamming the bus with exactly the right frequency to interrupt the ECM during it's scan of critical sensors. It was an extremely rare failure, and to Ford's credit they covered both the repair as well as my shop's diagnostic time. edit: To make it clear, I have seen 2 vehicles that still operated with a direct CANBUS short to ground, as well as a vehicle that had CANBUS shorted to 12V+. In these cases, aside from expected failures (such as the BCM systems not responding, or transmission limp-home), modules were able to fall back into either safe states (limp-home, in the case of the TCM) or just a dashboard warning light (in the case of BCM no-comms).
pfortuny 7y ago
Wow! Unbelievable. I mean, just SEPARATION. Thanks for the anecdote!

deleted 7y ago

[deleted]

zaroth 7y ago

“Bricked” is supposed to mean “permanently and unfixably ceasing to function”. That’s absolutely not what is happening here. The article is completely and inexcusably wrong on this point. The car won’t run when the eMMC chip fails, and Tesla solution is a new MCU board which costs $2,700 out of warranty. Not surprisingly Tesla is not desoldering and reworking just the eMMC chip. There are any number of components that can disable a car, from the battery to the starter to something with the ignition, electronics, anti-theft, etc. Sometimes the repair is as simple as a new battery, sometimes the repair is an expensive piece of hardware.

EpicEng 7y ago
Yet those things are crucial to the fundamental operation of the vehicle. We're talking about logs no user cares about here. It's just sloppy and a silly failure mode.
- zaroth 7y ago
  Anti-theft is not crucial to the operation of the vehicle, and that had certainly immobilized plenty of vehicles, sometimes in expensive to fix manors. Now if the article was that Tesla Model S has a chip which wears out and the board holding the chip is expensive to replace, and maybe even getting into why don’t they push a software update to lower the writes to that chip — I would not disagree. The article falsely claimed the cars are “bricked”. As it’s the main thrust of the article, it should be retracted. > However, until the company starts stocking parts like the eMMC chip, as well as release detailed service manuals to the public, Tesla is going to be looking at a number of newish cars dead in a junkyard real soon. They should stock a chip which is soldered to the board, and what, do reworks? That’s asinine. Newish cars dead in a junkyard? Totally false. It’s an expensive repair for a problem that could have been avoided, and hopefully Tesla will remedy with a firmware update.