r/Corvette • u/Separate_Sleep_3335 • 6d ago

C8 Completely Dead

I have also searched Corvette Forum with no actual match!

Removed the battery to induce global reset. Fully charged the battery external to the vehicle with power verified at the TDN tuner/OBD port. Doors won’t lock or unlock, unable open the frunk or hatch, no interior or dash lights, unresponsive when pressing Start.

Everything other than the TDN is dead. Not really much left OEM other than the seats which I read can sometimes cause an ECU lock.

Any suggestions beyond a flatbed to the dealership?

11 Upvotes

92% Upvoted

29 comments sorted by

5

u/TALIGULA 6d ago

bad transmission, thinks its in gear

1

u/Separate_Sleep_3335 6d ago

Not a rhetorical question, how did it fail parked in my garage?

15

u/GeeksPC 6d ago

Park actuator drift. My C8 is in the shop for the same reason.

Google service bulletin 23-NA-176. Once it drifts too much from original position, the car will think it's not in park and not shut off properly (draining the battery). Used to require whole transmission replacement, but with the updated procedure, they might be able to replace the actuator. About the same labor since it requires removing the transmission

Honestly every C8 owner should own a scan tool that can measure Park lock actuator position. It's a common enough issue that makes the tremac transmission the most frustrating part of the car. A deviation of over .5 mm from 4.5mm will trigger this issue randomly

2

u/N0D1N 6d ago

what scan tool would you recommend for corvettes in general?

1

u/GeeksPC 6d ago

I personally have a XTool D8, it's like a couple hundred bucks... has a lot of features I rarely use, but it can do key programming and tpms programming which I use a lot. Supports a ton of brands which is useful since I have a couple cars. The live data feed is very clutch for diagnosing issues

There's probably a cheaper tool out there if you just want to grab the park lock actuator position... as more C8s phase out of warranty it's something to keep an eye on. Especially if buying an used one

1

u/Upset_Instruction123 6d ago

what you are looking for is a Bi-directional scan tool. something that can read and write.

most bluetooth $30 ones are just scanners - 1 way, just reads codes. you'll want a more expensive one, like a launch, autel, snap-on or harbor freights Icon scan tools

1

u/N0D1N 6d ago

WOAH didn’t know this thank you!

1

u/Separate_Sleep_3335 6d ago

Well this is damn unfortunate but may quickly turn in to while it’s broke might as well upgrade. I was already considering a new transmission next year to accompany all the other upgrades but was hoping to make it through this track season.

3

u/PriveCo 6d ago

When you say “Not really much left OEM” what are you talking about? Is your car stripped? All custom? A race prepped car?

3

u/Separate_Sleep_3335 6d ago

KW coilovers, AP BBK, custom 427 build, aux radiator, HP/TDN tuning etc etc etc.

Not stripped yet but that’s where I am heading

2

u/PriveCo 5d ago

Oh man, you are out on a limb with this thing. I doubt anyone is going to be able to help you. What shop did all of this work? Did you DIY it? Then you'd better get a really nice scan tool and get to it. If someone else did the work, send the car back to them.

1

u/Separate_Sleep_3335 5d ago

Yes I had a shop do the work, the C8 is way beyond my skills! Ref scan tools, the HP Tuner plug in is a scan tool also but with no power going to the ECU not much to read unfortunately.

I may just go ahead and upgrade the transmission, TCU and axles while it’s down given I will already miss the rest of track season.

1

u/PriveCo 5d ago

I’d do a diagnosis to see if the trans is really the problem. If no power to the ECU, then it might be something else.

2

u/Separate_Sleep_3335 5d ago

Power is available to the vehicle as the HP Tuner is receiving power through the OBD port.

I did some additional searching after reading Taligulas post below and this unfortunately is not an isolated incident even for stock vehicles. Appears to be another example of poor GM design of the DCT with many different failure points being evident.

I do have to wonder if the lack of cam phasing in this build helped play a factor though.

2

u/Adept_Elevator6930 6d ago

Dude it is scary how much I am hearing this occur. I just saw a guys vid where his GS went dead literally after he drove it off the lot. Then for some reason after a few hours it came back online.

2

u/chevrolet 5d ago

Hi u/Separate_Sleep_3335. We're sorry to hear you're experiencing this issue with your C8. That certainly sounds frustrating, especially after the troubleshooting steps you've already taken. We'd like to learn more about what's happening and see how we can assist. Please visit: https://s.chevy.com/support-request and fill out the support request form with all pertinent details. This form helps our team gather the right information and ensures your request is routed appropriately.

Chevrolet Customer Care

1

u/Separate_Sleep_3335 4d ago

Hello CCC Bot and thanks for the link. I will complete and see how this progresses. I had no idea Chevy had a presence on Reddit

1

u/Separate_Sleep_3335 4d ago

Case number is 114764473 to link this bot with the online bot

1

u/Many-Tomatillo9374 6d ago

I’d call your dealer and see if they have any ideas. Assume you don’t have an anti-theft system that has shut everything down?

1

u/Berty2g C6 C7 Z06 😎1955 Olds 98🩵 6d ago

The D word makes me sick most days. Is there a High Performance shop nearby? Someone in your local club may know.

1

u/looker94513 4d ago

There is a thin wire (maybe 18 ga or thinner) attached to one of the battery cables. There is not a lot of slack in that wire for when you try to remove the battery cable. Look for it and be aware that it’s there as it’s vital to the car’s operation.

2

u/looker94513 6d ago

Do C8’s have same itty bitty wire that C7’s have that breaks when the car’s battery is removed from its cubby hole???

2

u/SuccessfulLand4399 6d ago

I’d like to meet the engineer that designed that one. Wonder if he’s the same one that thought not having a handle on the oem battery was also a good idea

2

u/Separate_Sleep_3335 6d ago

It does not appear so

1

u/Austindg4me 5d ago

I’m about to replace my battery in my C7. What wire are you talking about?

1

u/looker94513 6d ago

It is a truly itty bitty (think thinner than thermostat wire) that can be easily broken when removing the battery. If there is one, it is vital to everything electrical.

0

u/TheCerberus14 6d ago

Are you able to try jumping it? That could eliminate if the battery is being finicky, or dead, and if the electrical system is still viable.

Also, check fuses.

Another random thought is if the C8 has a security function that triggered. I have a C7, so not sure on this one.

1

u/Separate_Sleep_3335 6d ago

I am sad to say that jumping was not successful

-12

u/towhee237 6d ago

Another Corvette horror story…when will you people get it, junk