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The point is key switches as cut offs work fine when the component doesn't have major faults. Any other electrical control system could cause just as many issu

The point is key switches as cut offs work fine when the component doesn't have major faults. Any other electrical control system could cause just as many issues if designed poorly. Imagine if GM was just as sloppy with a push-to-start electronically controlled system that could shutdown due to EMF. And there have actually been issues with push-to-start systems. One model I can remember required the user to hold down the button to shut off power in an emergency, when the most common user reaction was to rapidly jab the button.

fnordfnordfnord 12y ago
>The point is key switches as cut offs work fine when the component doesn't have major faults. GP is correct. Cutting the electrical power to the power steering assist while the car is in motion is a design flaw. Can you think of any reason why the car should not have operational power steering when it is in motion[1]? [1] If you thought "for towing", that situation can be handled by the tow truck operator manually disabling the steering.
- Perdition 12y ago
  >Can you think of any reason why the car should not have operational power steering when it is in motion[1]? You can't have an electrical cut-out that doesn't cut-out certain components. The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay). If the ignition switch is not used for that purpose they would need to put a big red button on the dash like GP said. The ignition switch cutting all power has worked without incident in every other brand for many decades. The issue here is GM's incompetence, and I'm not inclined to the idea that they would have competently implemented another system. If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary).
  - fnordfnordfnord 12y ago
    >You can't have an electrical cut-out that doesn't cut-out certain components. Nonsense. Even the old mechanical ignition switch simply engages a number of relays and other electrical/electronic controls. >The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay). Fuel cutoff relays exist and have been in use since, not long after electric fuel pumps were put into use. >The ignition switch cutting all power has worked without incident in every other brand for many decades. In no way is that statement predictive of the efficacy of such a simple scheme going forward with more advanced electronic controls. >The issue here is GM's incompetence, No arguments there. >If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary). It is limited. It's more properly called power assist. It shouldn't be scary. Power steering is most useful only at low speeds.
  - Too 12y ago
    What's the chance that: 1. You get a fuel leak in the engine bay while driving. 2. There is not already another safety system detecting this. 3. The driver actually notices this while driving. 4. The driver decides to take action by turning off the key, without stopping the car first?! 5. For the scenario to be dangerous we are also assuming this leak is severe enough to eventually cause ignition and catch fire. This is like taken from a b-grade action movie and doesn't happen. Any scenario i can think of where you would require an emergency shutdown you would also want to get the hell out of the car asap. You could also imagine that things like cruise control "get jammed" but i find that extremely unlikely since software doesn't have the same wear and tear as mechanical components and sensors. Worst worse case you can always stop the car use the mechanical brakes or gearbox since those have more power than the engine. Unless we are talking about brake by wire or similar but those have _completetely_ different safety standards, there is also a reason those are not on the market yet.
jschwartzi 12y ago
GM failed to perform an adequate hazard analysis. Faultiness is inherent in any vehicle driven for a number of years, and as we've seen a single fault can disable many safety-critical features like ABS or Power Steering. The potential impacts of the failure modes of the key switch are quite severe, although in normal use the likelihood of any one is low. Because of the severity, some risk mitigation should have been in order regardless of whether the component "works fine" or not.
- deleted 12y ago
  [deleted]
- Perdition 12y ago
  I'm fine with that. I just think people are throwing out the baby with the bathwater by declaring mechanical ignition switches to be the problem (when they have worked fine for decades in every other brand).
Too 12y ago
There are also mechanical solutions to this, old Saab cars for example required the gear to be in reverse before you can remove the key.

fnordfnordfnord 12y ago

>The point is key switches as cut offs work fine when the component doesn't have major faults. GP is correct. Cutting the electrical power to the power steering assist while the car is in motion is a design flaw. Can you think of any reason why the car should not have operational power steering when it is in motion[1]? [1] If you thought "for towing", that situation can be handled by the tow truck operator manually disabling the steering.

Perdition 12y ago
>Can you think of any reason why the car should not have operational power steering when it is in motion[1]? You can't have an electrical cut-out that doesn't cut-out certain components. The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay). If the ignition switch is not used for that purpose they would need to put a big red button on the dash like GP said. The ignition switch cutting all power has worked without incident in every other brand for many decades. The issue here is GM's incompetence, and I'm not inclined to the idea that they would have competently implemented another system. If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary).
- fnordfnordfnord 12y ago
  >You can't have an electrical cut-out that doesn't cut-out certain components. Nonsense. Even the old mechanical ignition switch simply engages a number of relays and other electrical/electronic controls. >The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay). Fuel cutoff relays exist and have been in use since, not long after electric fuel pumps were put into use. >The ignition switch cutting all power has worked without incident in every other brand for many decades. In no way is that statement predictive of the efficacy of such a simple scheme going forward with more advanced electronic controls. >The issue here is GM's incompetence, No arguments there. >If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary). It is limited. It's more properly called power assist. It shouldn't be scary. Power steering is most useful only at low speeds.
- Too 12y ago
  What's the chance that: 1. You get a fuel leak in the engine bay while driving. 2. There is not already another safety system detecting this. 3. The driver actually notices this while driving. 4. The driver decides to take action by turning off the key, without stopping the car first?! 5. For the scenario to be dangerous we are also assuming this leak is severe enough to eventually cause ignition and catch fire. This is like taken from a b-grade action movie and doesn't happen. Any scenario i can think of where you would require an emergency shutdown you would also want to get the hell out of the car asap. You could also imagine that things like cruise control "get jammed" but i find that extremely unlikely since software doesn't have the same wear and tear as mechanical components and sensors. Worst worse case you can always stop the car use the mechanical brakes or gearbox since those have more power than the engine. Unless we are talking about brake by wire or similar but those have _completetely_ different safety standards, there is also a reason those are not on the market yet.

jschwartzi 12y ago

GM failed to perform an adequate hazard analysis. Faultiness is inherent in any vehicle driven for a number of years, and as we've seen a single fault can disable many safety-critical features like ABS or Power Steering. The potential impacts of the failure modes of the key switch are quite severe, although in normal use the likelihood of any one is low. Because of the severity, some risk mitigation should have been in order regardless of whether the component "works fine" or not.

deleted 12y ago
[deleted]
Perdition 12y ago
I'm fine with that. I just think people are throwing out the baby with the bathwater by declaring mechanical ignition switches to be the problem (when they have worked fine for decades in every other brand).

Too 12y ago

There are also mechanical solutions to this, old Saab cars for example required the gear to be in reverse before you can remove the key.