[Joeyk1982]

Thanks for any help with this issue!

I have a 2016 Camaro SS and I’m having a problem that the dealer can not diagnose.. After about 15 minutes of driving the thermostat gauge will drop and no longer read. When this happens the fans will run until I disconnect the battery. Also the rev match no longer works and the ac no longer blows cold. The car does this about 90% of the time after it’s been driven for about 15 minutes. I’ve replaced the coolant temp sensor and that didn’t fix the issue. I’ve also tried to add the extra ground cable under the hood with no luck. Once I disconnect the battery and hook it back up everything resets and works fine. I was thinking maybe it had something to do with some kind of module/relay that those four things run through?? Once again I really appreciate the help!

[bishopts]

Did you check for codes in the pcm? Sounds like a pretty straightforward p0128 code.

Thank you for using the correct section for issues. Here is another thread that might answer some questions.
https://www.camaro6.com/forums/showthread.php?t=636547

[Joeyk1982]

It never throws a check engine light.. the car still runs perfectly outside of these issues. I’ll check the thread you added, thanks!

Checked the other thread and I never have any power issues at all, it still runs perfect. It never has thrown a check engine light once. It’s been doing this for about 2 years now and all I have to do is disconnect the negative terminal on the battery and reinstall and everything is back to normal.

[bishopts]

Originally Posted by Joeyk1982

It never throws a check engine light.. the car still runs perfectly outside of these issues. I’ll check the thread you added, thanks!

Checked the other thread and I never have any power issues at all, it still runs perfect. It never has thrown a check engine light once. It’s been doing this for about 2 years now and all I have to do is disconnect the negative terminal on the battery and reinstall and everything is back to normal.

A generic code reader might not be catching the problem. The temp gauge dropping to nothing is a software response to something its seeing. If it were the temp gauge not reading coolant from the coolant being low then disconnecting the battery wouldn't resolve it.
If it were the coolant temp sensor failing then the pcm would turn on the light and the reduced engine power message.
If the thermostat were stuck shut the engine would overheat.
If it's the thermostat stuck open you will get a p0128.
P0128 is set from the factory as a 2 trip failure. So in order for it to set the engine light it will need 2 complete failure trips. That's from completely cold to operating temperature. If you're disconnecting the battery when you see the results of the first trip then it starts over. If you wait till it fails then check for codes while it's failed with a scanner that can see pending codes. You will probably see the pending p0128.
But... make sure your check engine light even works. They are led and they do die sometimes.

[Joeyk1982]

Gotcha, I think I’m going to replace the thermostat and see if that fixes the issue. Thanks for the help I really appreciate it!

[beowulf556]

Same thing happened to my 2015 tahoe. Ended up replacing the thermostat, that didn't fix it, then it was a sensor I believe.

[bishopts]

Finding out the code would be the best option. It really never hurts to put a new thermostat in for good measure but it it fixes your problem would be dependent on if a code for it was there. What code reader are you using?

[Joeyk1982]

I don’t have a reader, the dealer told me there were no codes when they had it

[bishopts]

Originally Posted by Joeyk1982

I don’t have a reader, the dealer told me there were no codes when they had it

Those guys... probably charged you a couple hundred dollars and no resolution too...
It would be in your best interest to purchase a proper bidirectional scanner. Autel mx808 or mx900 is what I've been using. Probably between $400-$500, it would give you the ability to look into all of your vehicles modules. So it would significantly improve your ability to get a proper diagnostic plan.

For example. You could check your ecm and tcm for codes and find out you have a transmission fluid temp sensor code. Then you can run the code by us, and we would be like "ah those are pretty common to fail in the temp sensor harness" and with that knowledge you could either fix it yourself or at least put your dumb dealership tech in the right direction.

Also it would work on your other cars. So you could be like "hey guys my nissan is throwing a p0101, any idea on what that is? " and we could suggest doing an air volume relearn with your fancy scan tool.

[Joeyk1982]

Ok thanks for all the help everyone! It’s greatly appreciated 👍