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Last night I was driving my volt and when I was stopping at a light, the brakes stopped working. There was a stabilitrack message and a Brake Assist Failure message as well as the Brake and ABS lights. I promptly stopped and waited a bit to turn it back on. It happened again within 4 minutes of starting it. My husband checked the codes and found that C120A, C12E9 and C12FE were being thrown but I can't find much for it. It was super scary and the Volt is now at the dealer.

Has this happened to others? How common is this? I typically have my girls with me and I have never had anything like this happen. The Volt has 41k miles.
 

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Note that you can also use the parking brake to slow the car. If you just pull the lever for a moment like you would to set the brake, nothing happens (a warning tone and message?) However, if you pull and hold, the car will engage the motor which will tighten the cable and stop the car. So it can work as an emergency brake if you're determined enough.

Note that the lever is bi-directional - to disengage the brake, you should be pushing the lever in, which I believe will not do anything while the car is in motion, but haven't tested.

Also know that GM cars have a manual "plan B" brake system if you lose power brakes they still work manually by pressing REALLY hard on the pedal. Like in the old days before power-assist.

C12FE is a problem with "ABS Pressure", I don't know about the other codes. Please post what the dealer repairs.

What you describe is not common. That's why posting the dealer's work order would be helpful so we can see what was replaced/repaired.
 

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That's a frightening experience, for sure. I have a 2013 as well. There have been a few reports of loss of brake assist over the years, which sounds like what you experienced.

The codes are as follows:

DTC C120A 00 Brake Boost Regulation Pressure Sensor Not Plausible
DTC C12E9 00 ABS Pump Motor Stuck On
DTC C12FE 00 ABS Pump Pressure Loss
 
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Last night I was driving my volt and when I was stopping at a light, the brakes stopped working. There was a stabilitrack message and a Brake Assist Failure message as well as the Brake and ABS lights. I promptly stopped and waited a bit to turn it back on. It happened again within 4 minutes of starting it. My husband checked the codes and found that C120A, C12E9 and C12FE were being thrown but I can't find much for it. It was super scary and the Volt is now at the dealer.

Has this happened to others? How common is this? I typically have my girls with me and I have never had anything like this happen. The Volt has 41k miles.
We’re very sorry to learn of this brake failure in your Volt, Nabetsi. Safety is of the utmost importance to us, and we completely understand your concern with this happening while driving yourself and others. We’re glad to see that your dealership is working to resolve this, and if you'd like any additional assistance while you work with them, please feel free to send us a private message.

Best,

Lauren E
Chevrolet Customer Care
 

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Last night I was driving my volt and when I was stopping at a light, the brakes stopped working. There was a stabilitrack message and a Brake Assist Failure message as well as the Brake and ABS lights. I promptly stopped and waited a bit to turn it back on. It happened again within 4 minutes of starting it. My husband checked the codes and found that C120A, C12E9 and C12FE were being thrown but I can't find much for it. It was super scary and the Volt is now at the dealer.

Has this happened to others? How common is this? I typically have my girls with me and I have never had anything like this happen. The Volt has 41k miles.
It is not common, and you probably have not lost braking, just braking assist, but it does happen. It sounds exactly like the situation I was trying to describe in a recent thread, and in older threads, involving braking on a slippery or bumpy surface with the transmission in 'L' mode.

Both times it happened to me it resolved itself after a shutdown and restart, and I was not able to retrieve any codes. I have not had it again, but neither have I duplicated the circumstances exactly as I rarely drive in 'L' any more, and never on a slippery road.
 

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BLUF, park vehicle, press OnStar button and ask them to arrange a pick up, then call local dealer and let them know what's going on and ask for a loaner.

Let the experts sort this out, and you have the Volt Advisor in your corner to assist should that be necessary.
 

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Discussion Starter #7
Thanks for the comments. I tried Onstar but it was not enabled. I called the dealer next and the service advisor asked me if just wanted an appointment, I explained the situation and she said I could get you in tomorrow. So I called back hoping to get someone a little more helpful, same person answered so I asked for a manager and was transferred to a voicemail. They have yet to call back.

The next morning we got the Volt to the dealer where the service writer said no loaner and this is not a big deal. I explained that I have two little girls and I could have gotten into an accident. I asked for the manager and he was the first person to understand or make me feel like they cared and wanted to fix it. I signed the $109 diagnosis fee, they put me in a loaner and I have been in it for 3 days without a call or any kind of status.

Is this normal for a Chevy dealer?

I should say that until this, I have loved my Volt. I go a month or more without pumping gas. It feels cool because of the gadgets and it's fun to drive a silent car but this incident is making me re-think keeping the car.
 

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Thanks for the comments. I tried Onstar but it was not enabled. I called the dealer next and the service advisor asked me if just wanted an appointment, I explained the situation and she said I could get you in tomorrow. So I called back hoping to get someone a little more helpful, same person answered so I asked for a manager and was transferred to a voicemail. They have yet to call back.

The next morning we got the Volt to the dealer where the service writer said no loaner and this is not a big deal. I explained that I have two little girls and I could have gotten into an accident. I asked for the manager and he was the first person to understand or make me feel like they cared and wanted to fix it. I signed the $109 diagnosis fee, they put me in a loaner and I have been in it for 3 days without a call or any kind of status.

Is this normal for a Chevy dealer?

I should say that until this, I have loved my Volt. I go a month or more without pumping gas. It feels cool because of the gadgets and it's fun to drive a silent car but this incident is making me re-think keeping the car.
I wouldn't let the behavior of one dealership change the way you feel about your car. You are perfectly justified in your expectation to be notified of the vehicle status in a more timely basis. I would call and ask for the service manager again and explain your concerns. More than likely, the manager will set the service writer straight.
 

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Discussion Starter #9
You are probably right. This is my first Chevy after having a long list of Japanese vehicles, I will call the dealer today and find out what is going on.
 

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Day 9: Volt at the Dealer
Called the dealer to get a status, I have not heard from anyone since dropping the vehicle off over a week ago. The service writer said he would have to walk back to check on the car. On hold for 15 minutes. He comes back says hello and hangs up. I give him ten minutes to call back but nothing. I call back and spoke with a different service writer. I explained what happened and asked if they could transfer me to the person I was speaking to. They transferred me to a random voice mail. I called back and asked to speak to the service manager, they took a message, said they would personally find him, hand him the message and I still have not heard back. At this point, I will just document what is going on here.
 

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It is not common, and you probably have not lost braking, just braking assist, but it does happen. It sounds exactly like the situation I was trying to describe in a recent thread, and in older threads, involving braking on a slippery or bumpy surface with the transmission in 'L' mode.

Both times it happened to me it resolved itself after a shutdown and restart, and I was not able to retrieve any codes. I have not had it again, but neither have I duplicated the circumstances exactly as I rarely drive in 'L' any more, and never on a slippery road.
Of course, I don't know exactly what happened with your car but I'm doubtful it is the same as this case. It is "normal" for cars with traction control to have a reduction in braking (or regenerative braking) on slippery or bumpy surfaces. People with other car models and brands complain about this sensation as well. The car is noticing a momentary lack of tire traction with the road and so it either slows acceleration (positive torque) or reduces braking (negative torque) momentarily in order to restore tire traction to the road. When this happens in a normally operating car, there is no need to stop and restart the car. If the car does this braking reduction when you really need to brake quickly then just push the brake pedal harder but since the tire has momentarily lost traction this might result in the ABS system rapidly pulsing the brakes in order to prevent the wheels from locking up and skidding on the pavement.
 

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Day 30 - The volt is still at the dealer. The Chevy dealer called on 7/27 to say they had been able to reproduce it and involved someone from corporate. They called again on Monday the 8th to ask if this happened after we replaced the brakes and I said I have not replaced them. Our Volt is mostly driven on charge. Then they called on Tuesday 8/9 to say that a tech was finally looking at it and working on it. I am assuming they will give us an estimate prior to working on it. I am grateful they provided me a rental because I could not go without a car.
 

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I called the volt advisor line today. They were very helpful. Within 15 minutes of calling them the dealer called and said if would be $2100 to fix the ABS Module Valve. I explained that the car has 40k miles with minimal gas usage and this must be a defective part. They are seeing what they can do and should let me know tomorrow.
 

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I called the volt advisor line today. They were very helpful. Within 15 minutes of calling them the dealer called and said if would be $2100 to fix the ABS Module Valve. I explained that the car has 40k miles with minimal gas usage and this must be a defective part. They are seeing what they can do and should let me know tomorrow.

Front Brakes Lock During ABS, Stability Control, or Traction Control Activation

FWIW: GM did issue a recall to replace the 'brake pressure modulator valve' a few years ago but this defective part affected a total of only 4 individual Gen1 2012 MY Volts...
 

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Day 37: Volt still at the dealer

I called the GM Volt line. They have been great help. Here is what has happened since my last communication. The dealer called back and said I had to pay $1500 which was half of the repair plus the cost of the rental. I said I was not paying for that, I had agreed to a $110 repair bill and would pick up the vehicle. I spoke to the GM-Volt line and the dealer called me back and brought the price down to under $1k which I was ok with paying. Then the service advisor called later that day (Monday) and said the Volt would be fixed by end of day (Tuesday) and we needed to pick up right away because we were in a loaner. I did not hear from them on Tuesday, so I left 2 messages without a response. On Wednesday around 3 pm I left another message. It's Friday and the dealer has not called. The GM Volt folks have been great. They just emailed to tell me the dealer needed more time.
 
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