Run Away Vehicle!

[skandalouz_08]

My wife had a scary incident happen yesterday when leaving the house in her Mercedes GLK. She backed out of the garage as normal and then put the car into drive and started to drive down our alley. Halfway down the alley the car started accelerating to high revs and she said the brake pedal felt like pressing on a brick and she couldn't get the car to slow down. She managed to turn out of the alley (luckily no pedestrians or other cars coming!) only for the car to keep accelerating faster. At this point she was able to throw the car into neutral before turning off the engine and pulling over to the curb. We were very lucky as she had both kids in the back and quick thinking ended up not hitting something.

We've had the car towed to the dealership but they can't seem to find anything wrong and no diagnostic reading. My wife is deathly afraid that if they can't find anything this is going to happen again while she's driving and she might not be so lucky this time.

Has anyone else heard of this happening before to a MB or any other type of car? Any thoughts on what I can check out that the dealership might have missed? Any help is appreciated before I start driving the car for a bit to see if it happens again.

[ThePenIsMightier]

Toyota accelerator stuck in poorly fitted floor mat.
Chronic with massive recall and lawsuits.

[Buster]

if I've said it once, I've said it a thousand times:

women drivers....

[ThePenIsMightier]

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if I've said it once, I've said it a thousand times:

women drivers....

First 20 seconds and feel free to get an education with the rest.

[Brent.ff]

“ The DOT concluded that, other than a number of incidents caused by accelerators hanging up on incorrectly fitted floor mats, the accidents were caused by drivers depressing their accelerators when they intended to apply their brakes. ”

https://www.caranddriver.com/feature...scare-feature/


That brick she was feeling mighta been the gas pedal?

[bjstare]

Brake pedal probably felt hard because it was actually the gas pedal buried in the floor.

[msommers]

Glad everybody is safe man, that sounds horrible. Obvious question even if dumb...nothing wrong with the floor mat placement right?

Otherwise it sounds like some severe electrical gremel, which if it wasn't obvious to th dealership diagnostics, will probably be lingering for awhile.

How do you feel about driving it instead for a week instead? There is probably no way she is going to feel comfortable in there again...

[AndyL]

Newer Mercedes have an event data recorder. You may wish to ask how to get that information from Mercedes - likely have to go over the dealer though.

[Tik-Tok]

Where was her purse at the time of uncontrollable acceleration?

[skandalouz_08]

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Glad everybody is safe man, that sounds horrible. Obvious question even if dumb...nothing wrong with the floor mat placement right?

Otherwise it sounds like some severe electrical gremel, which if it wasn't obvious to th dealership diagnostics, will probably be lingering for awhile.

How do you feel about driving it instead for a week instead? There is probably no way she is going to feel comfortable in there again...

Yeah, she definitely isn't comfortable driving it so will probably become my daily driver for the next week or so. See if it happens again to me and go from there. I think she would feel better if they actually found something at the dealership rather than saying that nothing is wrong.

Floormats aren't the issue as I was the last one to drive it on the weekend before she got in it Monday morning and I checked the pedals after this happened and there was nothing impeding them.

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Where was her purse at the time of uncontrollable acceleration?

She doesn't have a purse but the diaperbag with her phone, etc. normally sits on the front seat beside her or on the floor behind her seat. Not sure where exactly it was that day.

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Newer Mercedes have an event data recorder. You may wish to ask how to get that information from Mercedes - likely have to go over the dealer though.

It's a 2010 so I'm not sure if that is "new" enough? You would think they looked at that first when it was taken in but wouldn't be the first time a dealership misses things. I'll ask.

[Thaco]

Maybe accidentally hit the cruise/resume button somehow and it floored it and when she thought she was pounding the brakes it was actually the gas pedal on the floor?

[jacky4566]

Does she know you can always put a vehicle in neutral quickly by pushing the gear selector? Pretty sure its law you can always go into neutral without any interlocks.
Should be everyone's first instinct in a runaway situation.

[Masked Bandit]

It wouldn't be the diaper bag, way too big. Was she wearing shoes with a heel of some kind that could have gotten wedged in the pedals in funny manner? Unsettling situation for sure, I would almost hope it happens again when you're driving it so you can rule out something she did and then you know it's an issue with the car and not the operator.

[rage2]

Newer cars disable the throttle when brake pedal is pushed. Push both pedals down and it’s pure braking. Not sure if the 2010 GLK had that or not. I would check to see if that was a feature, and test that’s working. Even with a stuck mat or whatever causing throttle, brakes would’ve been engaged if the feature is present.

[JustinL]

If the events are as she described, that sounds like a stuck open throttle plate. The booster runs on vacuum, so she would have had one good boosted press on the brake pedal, but the second one the pedal would have come back up and felt like a rock. It would still work, but the effort to press is really high and the engine is still driving the wheels, so it seems ineffective. The GLK is a drive by wire, so there should be data for the pedal position and the throttle position. If the two are discrepant, then you've found the problem. If there is no fault, then it would most likely be the pedal unit sending a throttle open request and the engine responding appropriately to this.

It is scary when this happens, I had it happen on the back straight of Castrol in the rain on a test day. I went off pretty fast backwards, with the engine bouncing off the limiter. It's good to have a plan for this kind of thing and knowing how to find neutral (or clutch down), so good on your wife for that.

[ExtraSlow]

Scary, and really hard to nail down because while you trust and love your wife, it's also likely to be operator error. Being "right" in this case isn't a win for you.

If you do determine that the brakes and throttle work as rage described, you may want to have her test that theory in a parking lot to regain her confidence.

[JfuckinC]

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Toyota accelerator stuck in poorly fitted floor mat.
Chronic with massive recall and lawsuits.

This happened to me way back when in an acura 1.6EL, offramp from 16th west to barlow south was scary as fuck... haha

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Brake pedal probably felt hard because it was actually the gas pedal buried in the floor.

[sabad66]

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Does she know you can always put a vehicle in neutral quickly by pushing the gear selector? Pretty sure its law you can always go into neutral without any interlocks.
Should be everyone's first instinct in a runaway situation.

Thanks for the reminder. Gonna make sure my wife knows this

[schurchill39]

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Thanks for the reminder. Gonna make sure my wife knows this

Great call. Just had the talk with mine to make sure she knows

[AndyL]

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It's a 2010 so I'm not sure if that is "new" enough? You would think they looked at that first when it was taken in but wouldn't be the first time a dealership misses things. I'll ask.

Not sure on all accounts - but I know they often exist, farther back than many of us realize (and these were used to prove the toyota stuck throttle wasn't). But make / model specifics, and how to get that information for review - is way over my head.