GM Volt Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
A few days ago I had my windshield replaced by Safelite. All went well but now I'm stranded at a restaurant with my son on a 95 degree day. Car goes into " Initializing - wait to shift" mode but nothing ever happens. Everything else works fine Windows operate, radio and everything else works just no main battery power. Throws code P0C78. I tried clearing it with a code reader and it come right when I try to start the car again. I have tried disconnecting the negative on the 12v for 10 minutes same issue. I tried resetting the car by holding in power button for however many seconds and then walking away for a half hour. I have read that there are sensors on the windshield and if not hooked back up correctly they could be a problem. Any other ideas? I am pretty certain I will have to have the car towed to dealer at this point.

Thanks
 

·
Senior Member
Joined
·
1,027 Posts
P0C78 is bad. That's not from the windshield. That's just bad timing.

If it were a sensor you could use the "pocket" to start the car.
 

·
Registered
Joined
·
4,855 Posts
A few days ago I had my windshield replaced by Safelite. All went well but now I'm stranded at a restaurant with my son on a 95 degree day. Car goes into " Initializing - wait to shift" mode but nothing ever happens. Everything else works fine Windows operate, radio and everything else works just no main battery power. Throws code P0C78. I tried clearing it with a code reader and it come right when I try to start the car again. I have tried disconnecting the negative on the 12v for 10 minutes same issue. I tried resetting the car by holding in power button for however many seconds and then walking away for a half hour. I have read that there are sensors on the windshield and if not hooked back up correctly they could be a problem. Any other ideas? I am pretty certain I will have to have the car towed to dealer at this point.

Thanks
I recall viewing a video on Youtube that covered replacing a windshield on a 2017 Volt here. I recall that there is a bracket that needed to be attached to the new glass for the forward collision camera but no other wires. Maybe your issue is unrelated to your recent windshield replacement.
 

·
Super Moderator
Joined
·
6,424 Posts
A few days ago I had my windshield replaced by Safelite. All went well but now I'm stranded at a restaurant with my son on a 95 degree day. Car goes into " Initializing - wait to shift" mode but nothing ever happens. Everything else works fine Windows operate, radio and everything else works just no main battery power. Throws code P0C78. I tried clearing it with a code reader and it come right when I try to start the car again. I have tried disconnecting the negative on the 12v for 10 minutes same issue. I tried resetting the car by holding in power button for however many seconds and then walking away for a half hour. I have read that there are sensors on the windshield and if not hooked back up correctly they could be a problem. Any other ideas? I am pretty certain I will have to have the car towed to dealer at this point.

Thanks
Wonder if that code is similar to what is on the GM Spark.


 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
P0C78 is bad. That's not from the windshield. That's just bad timing.

If it were a sensor you could use the "pocket" to start the car.
I unfortunately feel you are correct. I'm going to try replacing the 12v battery just for fun and see if that would do it but I am not very optimistic.
 

·
Registered
Joined
·
2,360 Posts



If it is being caused by a faulty K10, you could attempt to remove the CHCM fuse and see if this makes any difference.







Otherwise, Gen1 Service Manual points to either a failed HPCM2 or battery pack as being possible culprits for this specific P0C78 DTC...good luck!
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
Just to let anyone interested know, the volt has been in the shop for 3 days still with nothing to report. I will continue my updates if we ever figure this out.

Thanks
 

·
Registered
Joined
·
1,374 Posts
Just to let anyone interested know, the volt has been in the shop for 3 days still with nothing to report. I will continue my updates if we ever figure this out.

Thanks
Probably would have helped the tech if you didn’t delete all the history for him... They should charge extra for the extra work.
 

·
Senior Member
Joined
·
1,027 Posts
Probably would have helped the tech if you didn’t delete all the history for him... They should charge extra for the extra work.
Codes are stored in history, FOREVER. You don't see them with a regular obd2 tool, but you can with GDS.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #12 ·
Probably would have helped the tech if you didn’t delete all the history for him... They should charge extra for the extra work

Thanks for such a thoughtful reply. As most know your history stays on the car when using an at home style tester plus I picture and write down everything. The tech says he appreciates the knowledge and help.

Also in the almost 7 years I have owned this car if I never trouble shot the issue myself I would have been in the shop at least once a year for random little issues like the battery coolant sensor, a few software bugs in the 2012 or just getting bad gas once. When your battery is out of warranty if you're smart you'll research and fix the things you can yourself.
 
1 - 12 of 12 Posts
Top