×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

GM Ignition Switch Defect Culpability
3

GM Ignition Switch Defect Culpability

GM Ignition Switch Defect Culpability

(OP)
Who is to blame for loss of life because of GM Ignition Switch Defect: Engineers or the company?

RE: GM Ignition Switch Defect Culpability

and what was the "fix",

A new key with a small hole in the center for the ring.

I have yet gotten the new key for my 2004 Monte Carlo and Silverado, but continue to get the notices.
Both of them also have complete dash stepper motor failures that was not even covered by warrenty
mad

RE: GM Ignition Switch Defect Culpability

Consumers,

Who wanted keyless entry transmitters integrated with the keys, which lead to larger keys, larger slots, and an undefined large offset-load because of that slot. It waan't the switch group that f'd this up. It was the keyless entry group. But the keyless entry group escaped blame.

RE: GM Ignition Switch Defect Culpability

"...wasn't the switch group..."

Readily available information is contrary to that. Apparently the switch itself failed to meet the stated minimum torque requirement.

Acknowledge in advance that the bigger picture would undoubtedly indicate multiple contributing factors, as always.

RE: GM Ignition Switch Defect Culpability

As more auto makers move to keyless ignition, this issue will be moot, or at least no longer relevant.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: GM Ignition Switch Defect Culpability

Keep in mind that the Toyota runaway crash was the result of a keyless ignition switch, as is a new crop of car theft vectors with their attendant risks of killing people while evading police.

RE: GM Ignition Switch Defect Culpability

2
Keyless pushbutton ignition replaces this problem with other problems - notably that the means by which the engine can be switched off in a panic-emergency (see above-mentioned Toyota runaway incident) by a driver who hasn't read and memorised the 700 page instruction manual isn't the same as in the cars (with keyed ignition) that the driver probably took driving instruction in and has potentially been driving for decades. With a normal keyed switch, you switch it off. With a pushbutton, what do you do?

A momentary prod at the on/off button? If you, as the auto manufacturer, accept a momentary prod at the on/off button as an instruction to turn the engine and entire powertrain off while driving, what happens when someone accidentally prods the button momentarily?

Hold it down for 3 seconds? A lot of them are like that. If the driver is in a panic and wants to turn the engine off, 3 seconds is an awful long time when the car is accelerating towards the back of a transport truck in front of you.

A very small number of manufacturers have gotten what I think is the right approach. Keyless, but not a pushbutton. A rotary switch in the same place where every other car has its keyed ignition rotary switch, and with the same switch positions. Want to turn the engine off? Same action as in every other car.

Both late model vehicles in my driveway have a plain ordinary keyed ignition switch, and I am fine with that.

The other problem that GM ran into is one that is unrelated to the type of ignition switch. What do you do with the car's safety-related systems (including, nowadays, electric power steering, ABS, and the airbag system) when the driver switches the ignition off (by whatever means, whether deliberate or accidental)? In the old days, that ignition switch simply cut power to (almost) everything. No more engine, but now, no more ABS, electric power steering, or airbags. Now one needs to switch off the engine immediately, but keep the safety-related systems running as long as the vehicle has non-zero indications from its wheel speed sensors, and *then* turn them off.

The GM cars that were affected by this had a traditional ignition switch that cut power to everything (except possibly headlights) - which has been the way it was since the beginning of having ignition switches. The consequence that evidently nobody had thought through at the time, is that accidentally bumping the ignition switch off while driving, disabled the engine, which disabled power steering, which made the car hard to steer (not impossible, but hard enough that someone not expecting it, and someone not used to applying serious muscle to the steering, would be caught off guard), which led to the car leaving the road and hitting solid objects with the airbags disabled because the ignition was off.

The law of unintended consequences, is inescapable.

RE: GM Ignition Switch Defect Culpability

AFAIK the majority of the fatalities were because the key switched off as the car was leaving the road and before it hit an obstacle. The key switch didn't cause the accident; it just turned off the airbag which might have prevented a fatality. I doubt there were many cases where the crash was completely avoidable and the vehicle being driven in a suitably careful manner before the crash. I know - an infinite amount of money is worth it to save even one life - but no one acts like that is true outside a settlement negotiation.

RE: GM Ignition Switch Defect Culpability

Quoting 3DD: "...I know - an infinite amount of money is worth it to save even one life..."
This is of course not true, and 99% of all people do not live their lives this way. Engineers certainly do not.
The "even if it saves one life" comment is not a thoughtful one, however sincere. Engineers should never say that, unless they are speaking in a Senate hearing.
If you do indeed believe that line about infinite spending being justified, then lobby to lower the freeway speed limit to 30 miles per hour and require all vehicle passengers to wear safety helmets - this is guaranteed to save thousands of lives every year, just in the US. You don't want to do that? Does that mean you don't care about human life? Of course not.
We have laws and codes and the tort system that are progressively refined - beyond that, you cannot engineer 100% safety without going bankrupt in a week.

RE: GM Ignition Switch Defect Culpability

"no one acts like that is true outside a settlement negotiation."

Is there a defect in the forum that cuts off parts of sentences?

RE: GM Ignition Switch Defect Culpability

3DD
I think you and I agree - I should have made note of that, and given you the credit. I was placing an emphasis on what you already stated briefly.
This is a important concept that underlines many of the failure threads (i.e. if only we designed for a little more capacity, this failure would not have happened).
No defect in the forum.

RE: GM Ignition Switch Defect Culpability

There was a ton of speculation locally around Detroit about one or more of the engineers responsible for the switch being charged with everything from hampering the investigation to manslaughter. I believe when everything was said & done, GM simply paid a big fine and warrantied every possible switch and other failure. My wife's 2010 sat at the dealer three weeks due to lack of new switches and we were loaned a new Silverado with free fuel the entire time. I don't recall details but there were six other recalls on that car, every one of them insignificant to the point of seeming silly yet for every one we got a loaner vehicle and free fuel until the issue was fixed.

RE: GM Ignition Switch Defect Culpability

CWB1 - " we were loaned a new Silverado with free fuel the entire time"
I wish I had a brother who owned a dealership - - -

RE: GM Ignition Switch Defect Culpability

BrianPetersen forgot to mention that the power brakes were also disabled if that pretty key turned off the ignition.
What bothers me personally most is the fact, that some people at GM knew about the problem and did not initiate the fix immediately. They knowingly played with the safety of countless people - me and my family including.
In my case - as soon as the ignition switch in my car was replaced, I drove it to another dealership and traded it for a non-GM vehicle.

RE: GM Ignition Switch Defect Culpability

Vance, no relations at any dealerships, tho I did explore the possibility of buying a GM dealership last year. I had the necessary funding but GM wouldn't approve the sale as I personally have no direct dealership managerial experience. As to the warranty coverage, I think GM basically gave up arguing with the govt.

Stateside we need to reevaluate our driver licensing as the fundamental knowledge and driving skill has dropped significantly over recent decades while vehicle performance continues to increase. JMO but if somebody needs power assisted steering or brakes to safely handle a small, modern, disc brake equipped sedan then they shouldn't be driving period. Heaven help them when a brake line pops or they have other mechanical failure.

RE: GM Ignition Switch Defect Culpability

Most drivers accustomed to the normal level of power assistance would not be prepared for the enormous (>10x) increase in steering and brake pedal force to achieve the same effect.

Cars nowadays aren't designed with consideration towards minimising control forces when the power assistance is not working. This was different in the old days.

RE: GM Ignition Switch Defect Culpability

Star for Brian, and decades of driving for both of us and our two kids.

We've had a car equipped with push-to-start since the end of February, our first equipped this way. I have looked at probably more of the owner manual than most, and I haven't seen anything about stopping the engine while moving.

In our situation anyway, the car is also equipped with a conventional manual transmission and pedal-operated clutch. So worst case it'd be hold the clutch pedal down and let the engine bounce off the rev limiter. Once stopped, put it in one of the upper gears and stall it out.


Norm

RE: GM Ignition Switch Defect Culpability

A couple of thoughts on power brakes and power steering:
Power brakes were traditionally 'powered' by engine manifold vacuum, with a reservoir and check valve to maintain boost for a stop or two with engine off. (yes, the boost unit is effectively its own reservoir)
Some vehicles use a boost unit powered by the power steering hydraulic circuit. No idea if there's a reservoir for that.
But- if the vehicle is moving under power and the engine is cut off, classically it would windmill, being driven through the transmission - even if the trans is an automatic.
But - not sure how that works with modern automatics - lots of computer control, I wonder if the trans even keeps friction elements engaged when power is cut.
Hmmm.
So, in an older vehicle the engine would still be driven by the powertrain and you'd have power steering and power brakes.
Now, maybe you don't.
Plus, the 'no airbags' situation.
double-hmmm.

Jay Maechtlen
http://www.laserpubs.com/techcomm

RE: GM Ignition Switch Defect Culpability

I believe modern brakes still use engine vacuum to boost pressure, although I'm sure there's infinitely more electronic bits between the master cylinder and caliper.

Most steering these days is electronic, so engine failure shouldn't have an effect unless your battery dies.

RE: GM Ignition Switch Defect Culpability

... unless "engine failure" was due to key-off, in which case, then what do you do?

Now that everything is electronically controlled, the thing to do is keep safety systems including power steering awake after key-off until wheel speed sensors report zero speed.

I am convinced that someone will find a way to file a lawsuit no matter what you do. Every time you think you have made something idiot-proof, someone comes up with a better idiot. (Every time you think you have made something lawyer-proof, someone comes up with a better lawyer ...)

RE: GM Ignition Switch Defect Culpability

Boost is typically <2x multiplier, not a 10x+ multiplier. That might mean somebody has to lift and use their foot rather than just their toe, but regardless, if you're losing control then you do what you have to. With modern materials and modern (read: large) disc brakes tho most econoboxes today feel like racecars after losing power compared to my classic clunkers' non-powered drums.

RE: GM Ignition Switch Defect Culpability

Quote:

I believe modern brakes still use engine vacuum to boost pressure, although I'm sure there's infinitely more electronic bits between the master cylinder and caliper.
Most of my vehicles use hydraulically powered electric brakes.
My 2001 GMC pickup has a hydraulic accumulator for the brakes. It gives between 1 1/2 and 2 1/2 stops.

Quote:

Boost is typically <2x multiplier, not a 10x+ multiplier.
What on earth have you been driving?
Contrast one or two fingers with both arms working hard to make minor direction changes. In the first days of power assisted steering, the power unit was added to a conventional steering ratio.
Now with full power steering the ratio is much higher.


Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: GM Ignition Switch Defect Culpability

Turns lock to lock in the old days were 4.5 or so,now, with heavier cars and big fat tires and geometry that is not optimised for steering wheel torque, 1.5 turns. On the move typical assistance levels are of the same order as the steering wheel torque, but there is a lot of shape to those curves, and at Park basically the sky is the limit - about 10 Nm. I have't tried key off while moving to see what happens to the brakes, perhaps on an empty highway I'll give it a go.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: GM Ignition Switch Defect Culpability

Tried it in my car at low speed last night (while pulling up to the end of my driveway, no traffic around or obstacles to avoid, etc). 2015 Fiat, ordinary keyed ignition switch, manual transmission, has electric power steering. I switched the key off with the clutch pressed in at about 15 - 20 km/h while coming to a stop.

Engine stops right away. Lights and instruments are switched with the ignition, those go off right away. Power steering stays active with the key off until the speed drops to somewhere near walking speed, then it goes off and stays off. Power brakes are vacuum servo and those remain power assisted due to the stored vacuum, as is normal with power brakes. Steering doesn't lock until you take the key out. I don't know what happens with the ABS, although I suspect that given that the vehicle knows it's moving even though the key is off, those probably stay operational while it's moving just like the power steering does. I obviously don't know what happens to the airbag system.

RE: GM Ignition Switch Defect Culpability

The wife's old Saturn would randomly lose its keys to the floor... while in motion. I stopped questioning what might happen and got rid of it... for another piece of crap (Nissan Cube, which I've droned on about in threads past).

Dan - Owner
http://www.Hi-TecDesigns.com

RE: GM Ignition Switch Defect Culpability

Quote:

What on earth have you been driving?
Contrast one or two fingers with both arms working hard to make minor direction changes. In the first days of power assisted steering, the power unit was added to a conventional steering ratio.
Now with full power steering the ratio is much higher.

My daily the last year has been my wife's old Chevy Cobalt, literally the vehicle that started this entire recall. Unfortunately I am able to attest that there is little difference between powered and nonpowered steering and braking on that model as the chime on ours has been intermittent since new, the LED screen is rather small and dim, and consequently we have run it out of gas a half dozen or so times in almost 200k. If the loss of power steering and/or braking was a significant issue on this model as several of you fellas are describing then I'd likely be dead as I've run it empty several times in dense Detroit traffic at 80+, not to mention the many local engineers driving/breaking (typically cobbled) test cars in similar circumstances. I'd wager most modern vehicles without power steering or brakes still steer and stop better than most of the 50'ish year old pickups I've restored. Reality happens, engines stop, and most folks deal with it accordingly.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

eBook - 10 Reasons to Choose CATIA on the Cloud
To compete in today’s fast-paced and competitive market, smaller and newer firms need a powerful platform that will enable them to compete with bigger players, without the heavy investments needed in computer hardware, software and personnel. Download Now
White Paper - Smart Manufacturing for Electronics
This white paper describes a transformative approach to electronics manufacturing made possible by the addition of Mentor Graphics to the Siemens family. It describes a completely digitalized strategy that supports both printed circuit board (PCB) and mechanical design and manufacturing, uniting the entire product lifecycle – from idea and production to customers and back. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close