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Discussion Starter #1 (Edited)
I've had my 2013 Volt (OHM-RIDE) for just a hair over eight months now and in that time I've had to have a faulty tail-light module replaced and recently had to have the "axle click" addressed but other than that it's been a fantastic and reliable vehicle for 17,000 miles.

Unfortunately this morning it completely lost it's mind.

I started out as usual and got about 2 miles away from my house when the dash lit up like times square and the alarms started binging away.

  • The large center Service power steering warning
  • Red BRAKE light
  • Service Parking Brake Light
  • ABS light
  • Traction control light
  • Check Engine light


Interestingly the power steering felt fine, but I lost all power assist on the brakes.

Now I could still stop, but it took a LOT of pressure. Now I've had power brakes fail before so I know how hard you have to push, and I'm a big guy with strong legs, but it took nearly all the strength I had to get the car to stop.

Pulling the parking brake switch did absolutely nothing. It was all up to pure leg strength.

If someone slighter like my wife, or an older/weaker person had been driving I'm not entirely sure that they could have successfully brought the car to a halt before rear-ending the next vehicle.

When I checked under the hood all fluid levels were normal including brake fluid.

The vehicle was just serviced last Friday (they replaced an axle and the CV joint to address the clicking) and I didn't drive it over the weekend so it's only been two "driving days" since the work was done, therefore I strongly suspect something wasn't re-assembled correctly.

I'll post follow ups as the situation develops.
 

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Any codes from OnStar?
 

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Discussion Starter #3
I'm afraid I didn't have time to check yet.
Basically I parked it in a nearby lot, hitched a ride back home, and switched vehicles so I could get to work.
 

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Scary! Too bad there isn't an easy way to experience lack of brake assist in an empty parking lot. That's something everyone should try out to gain an appreciation of the foot/leg pressure required to stop without it.
 

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Sounds terrible. Just a tip on using the parking brake: since it automatically releases when the car is in motion, you have to continually hold the switch up to keep it engaged while in motion. Also, shifting into low should provide regen braking. I know there isn't time for all of that during an urgent stop, but just pointing it out. The car would at least be controllable in a "limp to a safe spot" mode.
 

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Discussion Starter #6
Sounds terrible. Just a tip on using the parking brake: since it automatically releases when the car is in motion, you have to continually hold the switch up to keep it engaged while in motion. Also, shifting into low should provide regen braking. I know there isn't time for all of that during an urgent stop, but just pointing it out. The car would at least be controllable in a "limp to a safe spot" mode.
Good points. When I get the car back I may try the "hold the parking brake" thing to see if/how it works.

At that moment however there simply was no time to think. I had just crested a steep hill and was headed down towards the traffic light at the bottom when it happened and I basically had enough time to realize I had no power assist, cram down on the brake pedal, and reach over and pull the parking brake button once.

I stopped with about 8" to spare before I rear ended the other car at the traffic light.

I was really REALLY missing a mechanical emergency brake LEVER about then. The idea of messing with the shifter never even had a chance to occurred to me.
 

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Wow! In that situation, I would be in full panic mode, too. I did know ahead of time that you have to hold the parking brake switch to use it as an emergency brake, but doing that while all your weight is on the brake pedal would have to be very awkward. At that point, I would be seriously considering trying to jam the shift lever into park and letting the transmission self-destruct. It's good to talk through these scenarios ahead of time, so you don't have to think so much when it happens.

I have gone over the rolling restart procedure when the car accidentally turns off on the road with my wife, too. It's in the manual, but it's never happened to us.
 

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I had something similar happen a couple of years ago after a dealer servicing event. I don't recall at the moment what it was in for - maybe steering notch that was later addressed with a software fix. I only made it to the red light at the corner from the dealer when the dash lit up the same as yours. I think it was a loose harness of some type that caused it.
 

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The idea of messing with the shifter never even had a chance to occurred to me.
I use it routinely. I usually drive in D but find slapping the shifter into L very useful. I tend to drive with my right hand on the shifter. It would be second nature to use it. Try driving like this and see if it works for you.
 

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Sounds terrible. Just a tip on using the parking brake: since it automatically releases when the car is in motion, you have to continually hold the switch up to keep it engaged while in motion. Also, shifting into low should provide regen braking. I know there isn't time for all of that during an urgent stop, but just pointing it out. The car would at least be controllable in a "limp to a safe spot" mode.
I think the Volt disables regen if the ABS system is having issues, so "down shifting" to L may not have any effect. Maybe WOT, or one of the other experts, can shed some light on this idea.

VIN # B0985
 

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Discussion Starter #11
UPDATE

Just got off the phone.

The first piece of good news is that my insurance company will cover the tow to get the Volt back over to the dealer.

Then I spoke briefly with the dealership service manager who said that since my wheel/axle was disassembled for the previous repair that it's possible that a wheel speed sensor might have been damaged and if that turns out to be the case it will be a covered repair.

will continue to update.
 

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A quote from another thread, eerily similar:

"...I applied the brakes they initially felt normal, then there was nothing. I had the pedal to the floor and the car would not stop. Some dash lights came on and it began to "ding" ... The brake light is on, the ABS light is on, the traction light is on, and this is odd, the message that says "Service Power Steering, Drive with Care". Power steering is fine."

This was the thread linking the problem to wiring interference from an HID upgrade kit, although not everyone was convinced.

http://gm-volt.com/forum/showthread.php?165913-Not-anApril-Fool-s-joke-HIDs-NO-BRAKES!&highlight=hid+brakes

Whatever the problem, it is pretty alarming that the failure mode is a severe loss of braking performance.
 

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A quote from another thread, eerily similar:

"...I applied the brakes they initially felt normal, then there was nothing. I had the pedal to the floor and the car would not stop. Some dash lights came on and it began to "ding" ... The brake light is on, the ABS light is on, the traction light is on, and this is odd, the message that says "Service Power Steering, Drive with Care". Power steering is fine."

This was the thread linking the problem to wiring interference from an HID upgrade kit, although not everyone was convinced.
...
I've seen many reports of after market head light kits inducing wild problems with many systems. It doesn't sound to me like that is the problem here, too much of a potential coincidence with the recent repair.
 

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On Gen 2, a bumpy road or even hitting one big bump is sufficient to disconnect regen. It feels like brake failure at first. Not sure how the system resets after this happens.
 

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Discussion Starter #16
On Gen 2, a bumpy road or even hitting one big bump is sufficient to disconnect regen. It feels like brake failure at first. Not sure how the system resets after this happens.
Smooth road, downhill, 25mph. and then POOF, no brakes.
Any mods done to car (the LED project) have been in place without issue for at least 6 months.
 

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Could also be a sudden issue with the 12v system? A shorted 12v or a 12v that suddenly drops to zero volts might cause weird stuff to happen.
 

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My manual says nothing about regen being disabled under any circumstance, unless I missed it. I search online and all I find is this or that talked about, almost all of it on this forum. This one explanation seems to fit best (though I have never experienced any loss of braking so I can't know):

This is how the car was designed. During regen the car cannot do anti-lock braking. So when the car detects what it thinks is a slide it will disable the regen.

This is why when driving in the winter I like to drive in D vs. L. This way when the regen is disabled the car then replaces the regen with an equivalent amount of friction braking (there is a terrifying sensation during the transition but it actually happens very quickly though it doesn't seem like it at the time).

Or if you're in L mode when slowing keep your foot lightly on the brake pedal so that the car will engage the friction brakes if a loss of traction is sensed.
I vote for a speed sensor problem.
 

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My manual says nothing about regen being disabled under any circumstance, unless I missed it
Under normal braking operation (using the pedal), if slip is detected and ABS kicks in, regen is dropped and it switches to all-brake pad. It will blend regen in back to normal instantly as soon as it decides ABS is no longer necessary. The screen will flash low traction (not the icon, an actual popup message).
Normally, this is a fraction of a second transition. When it gets scary to people is when they're in L or braking lightly and hit a bump - feels fast and out of control because proportionately, the pedal pressure does not give much braking (if any at all if just decel coasting in L and no foot on brake)

In OPs case, the failover switch did not work (because brake booster did not work), so reduced braking performance was the result.
Note that operative word is reduced as there are still the 'last resort' mechanical brakes that you need to press HARD for.
Except in cylinder/line failure (which can occur in any vehicle), these will always be there for emergency braking.

Cylinder/line failure and you're SOL.
 

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Cylinder/line failure and you're SOL.
But in that case, you should only lose braking in two diagonally opposite wheels. Still loss of some braking, but not all.
 
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