SickRick

1SB/Z-51/MN6

So, I'm coming around a corner (left hander) at low speed (15-20MPH), kick it into 2nd and hit the gas - what I EXPECT is the the rear wheels will spin a couple of times, the rear will kick out a little, and AH/TC will kick in, stop the spin, straighten out the fishtail, and I'm on my way...

What I GET is an rear end that keeps traveling and NO AH/TC, I start to steer into the spin to correct, and the rear end swings around the other way, the car gets sideways, and there's nothing left to do, but hang on and see where it lands. My LAWYER (who was in the passenger seat) tells me the last words out of my mouth (before we hit the parked car & tree) was; "the car is not supposed to do this".

Street was dry, no gravel or debris on the roadway, tires are worn, but not down to the wear bars yet.

What's interesting is on Monday (day before the accident) I get a "Active Handling Recalibrating" message on the DIC. No "failure" or "service soon" messages. I get the feeling I might be the victim of an onboard computer malfunction, as I don't recall the AH/TC ever kicking in. I've got close to 8,000 miles on this car, so I'm pretty familiar with its handling characteristics - I've had it on the "amateur skid pad" (mall parking lot in the middle of the night), so I pretty much know where AH/TC kicks in.

I'm curious if there's a way to tell if there was a malfunction (or NON-FUNCTION) of the systems at the time of the accident, for two reasons.

one - if there WAS an equipment failure, then GM (not me) may be liable for the accident (no injuries, damage a parked car & mine).

two - I want to KNOW these systems are WORKING PROPERLY when I pick up the car from the body shop (promised in 20-30 days - ughhh), as I'm not really going to trust the damn thing.

These systems are supposed to be our safey net, so we can operate these cars with less worry about them "getting loose" on us. While onboard computers are no excuse for "driving like an a$$", I DO EXPECT THEM to do thier job if I get into trouble...











rear bumper cover, rear drivers quarter, dings on 3 of the rims, drivers rear suspension tweaked (front of wheel pointing outwards), trunk lid cracked, front cap done in + whatever OTHER damage occurred underneath the fiberglass. Body shop manager tells me its far from a total (RATS). I got a couple of bruised ribs, my passenger got shook up, and did about $2K worth of damage to the back of the Honda Accord I slammed into (who wasn't supposed to be parked the swale - we WOULD have come to rest of the grass without hitting ANYTHING if the car wasn't parked there)...

Rick

C64BC

I'm glad you guys are okay. But purposely going into a spin waiting for a safety-net is always a recipe for disaster. Try to prove AH not stopping a spin on dry pavement as GM's liability will proves fruitless in any court of law, because without the roads being wet you will be considered wreckless driving as is. Did you get charged? If not, consider yourself lucky!

There have been several posts were it has been reported that TC/AH is not always consistent, and it probably never will be consistent because there are so many physical factors that relate to spin-outs.

Good luck getting you car fixed quickly, and accurately.

Might i suggest a performance driving school. This would have helped you correct and not depend on TC/AH to save your butt. They actually have part of the training specifically designed to control your car in the scenario you mentioned. Good luck

larry_chip

i've had the same thing happen to me the first week i bought my car, i made a left turn on Park Ave doing about 10-15 mph in first & i hit the gas a little to bring the tail out & thinking the same thing you were "AH &TC Will kick in & straighten the car out BUT NOPE!, my tail went LEFT & RIght i got control of the car intime but i will never trust that AH & TC Ever again, i learned my lesson with this car & now i know what i can & Can't do.

Tampa Vette

TC and AH will NOT prevent a spin-out. It is there as a back-up to assist the driver, not a safety net.

I would never step on it in a corner, regardless of TC/AH. I don't trust technology as mush as I trust myself.

Good luck SickRick! In no time she'll be lookin as good as new and a lesson will be learned.

plaster

I disagree with couple of the above posts. While we can all say "you shouldn't have done that", it is still up to GM to provide a properly working product. Something that works sometimes is not a working product. My C5 always, ALWAYS, kicks in at the same about the same time. And you should have probably received a ticket.
The factors involved in these low speed turns would not upset the computer. I remember back around 2000 an interview with the guys working the system in a Cadillac. There were very few things they could do to the car that would confuse the computer.
It is a safety net, but one you paid for and one that should work as intended. Nobody would question the fact that GM would be at fault if the ABS did not work suddenly.

And I find it very humurous that your attorney was with you when this happened. That's just too perfect.

MitchAlsup

We have seen a number of cars do exactly this when overdriven by a driver who is not prepaired for this kind of dynamic situation while driving.

The BMW M3s seem to be especially prone to crashing in the opposite direction of where a car without AH/TC would crash.

An older car, entering a spin, will leave the road in the direction of travel; typically backwards or with significant rotational inertia.

A car with AH/TC will start to spin, the car systems reacts BEFORE the driver and tries to save the car, then the driver starts to attempt a recovery (unaware that the car is trying to recover on behalf of the ham fisted driver), result: two different mechanisms are attempting to perform similar spin correcting manouvers. When the initial energy of the first spin is compensated (yaw put in control), we now have twice as much force trying to put the car back on rather straigt arc, and the car (violently) snap spins towards the inside, in an unrecoverable manner.

Several M3s driven by new track drivers (with rather high testosterone levels) have crashed towards the inside of T7 at TWS in exactly this manner. Every other wreck I have seen in T7 has been to the outside (where there is nothinig to hit.)

Back to the first statement in the second paragraph: "What I GET is an rear end that keeps traveling and NO AH/TC" I suspect that AH was in the process of deciding if you were in trouble, and if so what would be a prudent series of actions to take (1/10-1/4 second to determine this info) and/or making some subtle adjustments to the thrust at the rear tires (increasing pressure on the outside rear brakes to divert thrust to the inside rear tire) that you did not feel because you were "in over your head". By the time you started to react, and the AH was already mid-reaction; it was too late.

Moral: AH/TC is a system designed to give the average drive additional margin of error; it can be fooled when you try to "drive against" its operating parameters; And when 'fooled' it is often worse than no AH system at all.

mikeyc6

SickRick, sorry about your car and glad no one got hurt. I think you have a misconception regarding what AH/TC are supposed to do for you. Doing what you did is the equivalent of going 60 MPH and slamming on your brakes 10 feet before a brick wall and then saying "but ABS should have stopped me". There are both technical and physical limits to any system and AH/TC wasn't designed to recover from someone doing a "Hey, let's see if it can keep me from hitting this tree" test.

There is no way to know for sure, but you may have pressed the system way beyond the limits of what it was designed to recover from! There are also many limitations of the design. For example, it is physically impossible to computer-correct a car that is sliding 90 degrees sideways. Some assumptions have to be made regarding wheel rotation speed, the fact that not all 4 wheels are always touching the ground, and many many other factors. AH/TC can be good but it can't break the laws of physics and they are never a substitute for good driving. And then there is the feedback issue already mentioned. The Air Force fought with this for literally decades until they got a system that worked properly in their computer assisted figher jets. Indeed two systems trying to make corrections at the same time can cause feedback loops and can be worse than doing nothing at all. As a result, these AH/TC systems are not designed to take total control of your car and get you out of a dangerous spin. They are also not designed to be able to steer the car like you can. There's only so much "steering" you can do by modulating the brakes!

I know... you wish you had known this before you ran that test. I really don't mean to sound like I'm preaching or being an **** when I say this but there is really no other way to say it. Testing your car by intentionally putting yourself into a dangerous spin on a public road is just insane! If you want to test the limits, there are times and places to do it, but I personally would never do such a thing unless I'm on a private course and have enough leeway that I know that even if I can't recover, I won't hit anything.

Sorry, but I think you'll be laughted out of court if you try to pursue this one. Best of luck in getting you back on the road in a hurry in any case!

Mike

plaster

Maybe I read his original story wrong, but I didn't get the idea he was 90 degrees around or that the AH kicked in at all. I understood that it started to go abit, and when he realized that AH was not correcting him, he had to overreact quickly to try and save it. I have gone around a very similar corner many times (2nd gear, approx 25-30 mph), blipped the throttle to start it around, and it has always cut my fuel and stopped the slide.

mikeyc6

I was simply pointing out that there are situations where AH cannot to its job and may not activate if it determines that doing so is futile. It sounds like Rick has some experience with such maneuvers and it appears that this one was severe enough to where he himself couldn't save the car. If he is indeed a decent driver and couldn't save it, I think you'd be hard pressed to expect a computer to be able to do it with the brakes only and no access to the steering wheel.

Mike

Scissors

TC/AH are there as a safety net. You should always drive as if you don't have them at all and let them be there to save you from the unexpected.

Driving in such a way as to expect TC and AH to kick in is an error on the driver's part, not GM's--regardless of whether they kick in or not.

EuG

I agree with a lot of what’s been said about the limits of what AH can do.

But here’s another thing:
What makes you think AH was even supposed to kick in, in the first place??
I regularly do 180s by cranking the wheel and giving it some gas. AH doesn’t interfere at all.

I think it’s programmed to correct the car only when you’re going much faster.
I would be upset if AH wouldn’t allow me to do things like power-sliding etc , an fortunately it doesn’t.

Sorry about the accident….

houston_aggie

Sorry about your accident, I was in a similiar accident a couple of months ago (the post is here somewhere). Turning 90 degrees left from a stop, 1st gear, too much pedal, rear end breaks loose, wasn't prepared, and car hops the median. Only minor damage (the weld at a radiator support joint broke), but I now definitely respect what the car can and can't do. AH/TC didn't help me at all.

When making similiar turns now, if it breaks loose on me again I know what to expect and know how to correct it. It's actually kinda fun to do when there aren't any other cars around and there are no obstacles.

A seperate but related issue, I attribute some of the breaking loose to the run-flat tires. From everything I've read, they are made out of a harder compound and just don't grab as well compared to any non-run flats. My next set of tires, I am considering non-run flats, but that's another topic widely debated here.

plaster

I started thinking the same thing at first - maybe he was going too slow. However, mine (C5) kicks in at about the same speeds. I am only partial throttle. Hell, maybe there is something wrong with mine. Whenever I want to stick the tail out or flip it around, I must turn it off.

plaster

His fault for playing around. Agreed. So when his wife takes the same corner, swerves to avoid hitting a kid (sounds like it was some kind of park setting) and the AH does not right itself and she careens into a tree, there is no reason to be upset that AH didn't help? Then why have it?

Again, I'm assuming that it is also designed for low speed spins.

EuG

TC must be OFF, but you should be able to do with AH on.

TommyV

A liitle known feature of the C6 is the AHS (*** Hole Sensor) in the passenger seat. When it detected the attorney, it activated, and shut off the TC/AH. If you wouldn't have crashed, the passenger door would have opened and the *** Hole would have been tossed out.

MitchAlsup

To placate the laywers when cars got more than 300 HP.

SickRick

'preciate the comments (and sympathy)...

I've been to a number of performance driving schools (back in my BMW Club days), so my skill levels are pretty up there. Yes, how well I know this is NOT a BMW (not knocking it, I love the car).

I'm also well aware of what AH/TC is capable of correcting...

I'll clarify a little (if I can). It wasn't a stop sign right turn, where I gunned it from the stop, it was a regular old corner/turn in the road that is a ninty-degree turn (non-banked).

Initially I used to curse the AH/TC, when I was trying to get a couple of spins and some kick out, but I've gotten used to it and drive with it (though some might consider that against it). The car had gotten far enough into the counter-clockwise spin to where I figured AH wasn't going to save me, so I counter-steered into the spin and tapped the brakes. At that point the rear swung back around clockwise and I got sideways. I know once you're sideways, you might as well be on Space Mountain, cause you're only along for the ride.

The point is, that you get used to driving with the computer systems, and DO COME TO DEPEND ON THEM TO BE CONSISTANT. The thing that causes me to have suspicians, was the RECALIBRATING message I got the day before - as the AH/TC had always been consistant before that point. My other concern is, will I be able to trust the car to behave consistantly in the future?

These systems are there to assist in the driving experience, and they ARE far more refined than the one's I've driven in other GM cars (roomates Z-28, etc.). How confidant are YOU going to be, next time you punch it out of the apex of a turn, and find yourself looking at oncoming traffic.

No, the car didn't make me punch it out of the turn, but the expectation of assitance if things got out of hand allowed me to execute the manuevour with confidence - confidence (and trust) that's going to take me awhile to rebuild/re-establish.

On the lighter side, 3 of the wheels got ding'd - the body shop manager told me I could apply the price of replacement towards any aftermarket rims I'd like...

Rick

mikeyc6

There are two sides to every story. The other way to look at this is that AH/TC makes people think they can do things in their cars like defy the laws of physics, fly, avoid crashes, etc. So just knowing that the car has AH/TC can make you a bad driver because you learn to take real driving for granted and depend on it to wipe up after your mistakes.

I agree with Scissors. You need to drive the car as if TC/AH aren't even there. I don't "test" my ABS brakes at a 4 way stop by putting the brakes on at the last minute because I know they are there. Same story with AH/TC.

Mike

Cookee

Rick,

Happy you guys are safe and sorry your baby got hurt.
However how could anyone truly think GM should be responsible for you accident?
Oh yeah, a lawyer could. The CPU located between your ears was the primary collision factor, not GM.

A Tip: Next time your going sideways pull your foot from the gas pedal, it will help save you money!

Anyway, I am glad you guys are safe!