Is anyone else experiencing brake issues [failure]?

[IllinoisSpark15]

Glad to hear they fixed your car, I'm surprised it took so long. It also seems like your repair consisted of replacing different components than mine. To be honest, that concerns me. Thankfully I haven't experienced any further issues since the dealer repaired it. I'll be sure to post on here if I experience any further issues. Good luck twinsemi.

 

[ZipZap]

Shoot. My car started to have issues with Brake Assist/Stabilitrack/ABS about a week and a half ago. The hydraulic and regenerative brakes still work, but it requires it a lot more force for the hydraulic brakes without the brake assist. They start working again when I turn the car off and start it up again (though the quickest turnaround I've tried for this is a few hours). Since the problem first appeared, it's happened 5 out of the last 7 times I've driven the car, usually after driven around 7-10 miles or so, though once, it happened within a block of the start of the trip.

The car has mostly been with my local dealership since the problem started, but I just got it back with the issue unrepaired for the second time this evening. The first time, they replaced my 12V battery (they said there were codes for low voltage on a lot of the submodules of the car), but when did a capacity test on it (I asked for the old one back) it had about 42Ah, which seems surprisingly good for a 4 year old lead acid battery originally rated for 50Ah that has been through a few Las Vegas summers.

The second time, they said they were unable to replicate the problem after 2 50 mile drives, which seems unlikely to me, given my experience since it started. I'm going to drive it the next couple of days to see if I can figure out some kind of pattern to reliably reproduce the problem quickly, but I'm starting to wonder how worth dealing with the dealership is. That $300 set of service manuals is starting to look more and more attractive. Is there a better way (more detailed anyways) to get error codes that the cheapo bluetooth odbc modules and the torque app?

 

[IllinoisSpark15]

Sorry to hear I'd your troubles Zipzap. Your Spark issues sound similar to what mine had. Have you spoken to your service department about the parts (and part#s) that were replaced on my car? This may give them a new avenue to explore in their repair diagnosis. My vehicle has had no further issues after those parts were replaced.

Apologies, but I don't have an answer to your last question. Please keep us updated on your vehicle's progress.

 

[ZipZap]

They only replaced the 12V battery the first time and didn't replace any parts the second time.

This morning, I got the alerts to trigger twice. Shortly after the problem occurred the first time, I stopped and turned the car off for a bit less than a minute which reset re-enabled the stabilitrack and brake assist systems. Both times the errors were triggered, I was sitting at a stop light after having driven for about 10 minutes, and I noticed the brake sinking to the floor under constant light pressure. After perhaps 10-20 seconds of the pedal sinking, the stabilitrack and brake assist errors popped up. Last night (after the car had thrown those errors at a stoplight) I noticed the pedal slowly sinking as well (at several stoplights after the brake assist system had been disabled).

Also, I got an error code using a cheap bluetooth ELM scanner and the Torque app:

C12b1

Torque didn't know what the code was.

-Nathan

 

[IllinoisSpark15]

Yes, very similar to what I was experiencing. It can be terrifying if the pedal pressure goes out at highway speeds which happened to me. I hope you get this resolved soon. I know how frustrating it can be. I'll be looking forward to your updates...

 

[ZipZap]

Good to know. I've been driving very conservatively with that car since the problem first appeared.

Is looks like that code is probably "DTC C12B1 00: ABS Master Cylinder Pressure Sensor and Brake Pedal Position Sensor Not Plausible"

https://www.autocats.ws/manual/chevrolet/tis0911/en/documents_2012/Volt/start_Volt.html

 

[ZipZap]

I managed to drive it home carefully enough to avoid triggering the issue until I pulled into my driveway and held down the brake pedal at the right speed and pressure to throw the warning errors. Hopefully that's good enough for the dealership to figure it out.

 

[IllinoisSpark15]

Parts and numbers:
Brake Pressure Modulator Valve #23283683
Electronic Brake Control Module #23154359

These are the parts they replaced in my car, and I've had no further issues. They are obscenely expensive at ~$2700 parts & labor.
Does the dealer have it again? I remember you mentioning they had it for a bit, but were unable to reproduce the brake issue while they had it.

Keep us posted, and I'll try to answer any questions you might have.

 

[firefox2026]

I just bought a used 2015 Chev Spark EV today. It was fine when I drove it around for a test drive. However when I brought it home and then went to dinner. I started having this exact intermittent issue cropping up now with the power brakes shutting down. Luckily I sprung for the warranty but I worried if they will cover it or if they will wonder if I knew it was that way when I bought it. The dealer might have known about it but I didn't, but will they believe me lol.

 

[IllinoisSpark15]

Sorry to hear you are having this issue FireFox. Can I ask what state you are in? I have a theory that cold weather may be a factor. This issue happened to my car once again, 6 weeks ago. The power brakes stopped working and the abs service light lit up on the my dash screen. Coincidentally, it was also the first night of the season when the temperature dropped below 20°F. I restarted the car, and the issue cleared and hasn't returned. It can be a frightening experience. I hope your mechanic can diagnose the issue properly and get you back on the road safe. Best of luck...

 

[firefox2026]

Thanks that is good to know but a bit dis-concerning your still having problems. It too was during cold weather in Colorado maybe in the 20-30s(F) range or lower. They decided to replace the break petal sensor first but as I feared that didn't work. They were going to replace the break booster (which I think is actually the same thing as the modulator valve). I not sure if they are going to want to do that under the warranty since the part is so expensive, but the owner of the dealership wasn't sure yet.

 

[firefox2026]

So I was going to get the part number for the part they were replacing tomorrow, but as I researcher it more I think they are replacing the master cylinder (which includes the booster). Looking at it that might be the bad part (I hope). I do notice that the break peddle on mine was slowly falling into the floor and that is when the fault gets triggered.

What to do when break peddle goes to the floor..

https://www.youtube.com/watch?v=DzS4VOJwTCU

 

[firefox2026]

So the part they are replacing is the master cylinder which is about a $600 part - #95489495

It sounds like from what I gathered out of the service repair manual was to replace the modulator valve if the symptom involved the break pedal also kicking back when the fault occurs. As far as I know that wasn't happening mine it just fell to the floor slowly suggesting an leak someplace.

I worry that if it is the master cylinder that it may have a design flaw or something since this doesn't seem to be an isolated issue.

 

[firefox2026]

Well it seems like they say they got it fixed with the new master cylinder. Going to go over and pick it up so I keep my fingers crossed that it doesn't act up again. Was really excited about getting an EV so I hope I don't end up disappointed in the end..

 

[firefox2026]

Well the good news is the brakes were working fine as far as I could tell, but it still was triggering a abs code sometimes after you powered it up. They looked at it again and its saying that the computer was saying there was a leak from one of the front wheels. The mechanic surmised that they didn't bleed the brakes enough and was going to bleed it again. I just getting a bit frustrated I was hoping to get to have my car finally but not yet. Hopefully they will have it done tomorrow morning.

 

[firefox2026]

OK so I guess they ended up having to vacuum bleed the brakes in order to get the air out of the system. So far so good no errors or anything and its working good now.

Hope it stays that way for now....

 

[IllinoisSpark15]

That's good news for sure. Please keep us updated if any further brake issues crop up.

 

[firefox2026]

Well here I am again.. I had a slightly different problem crop up with the breaks but this time it do it more randomly while you were driving. It ended up at the dealer because it had so many weird problems they couldn't figure it out. Now even the dealer can't figure it out. It sounds like there all sorts of communication issues or something. I fear I got a real lemon. I didn't realize from the service record that the breaks had numerous problems before this from the original owner. I don't know if anyone might have a clue of what I should do.

 

[firefox2026]

I should add after looking at the DTC listing again I think maybe some of those were just in memory and not active. The active one is DTC code C0561- System disabled symptom code is 4B - system calibration not learned. I think the used car place said they would try to re-load the calibration data and it would fail loading. The dealer seems stumped over it and its been in the shop for about 3 weeks now.

 

[NORTON]

.... The dealer seems stumped over it and its been in the shop for about 3 weeks now.

Say What???
Doesn't the dealer have the phone number for Tech Support back at the Mother Ship?
Is it a sign of giving up to call in for tech support?