GM Volt Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
Ok, so here it goes I replaced the bearing in my volt for the electric motor. It was actually really easy but now i'm in a nightmare. My friend disconnected the msd while the 12 volt battery was still connected and so now neither the ice engine or electric engine will run. I get the service high voltage system. Now I have tried resetting everything through gsd using the factory procedure, if this happens but no luck. Does anyone have any insight on this, my next option was going to be to upgrade the firmware and see if that works.
 

·
Registered
Joined
·
367 Posts
From what I know, you MUST disconnect the 12v battery BEFORE pulling the main disconnect. I assume the dealer needs to reset something, or many people use a VCX Nano to do it yourself, something like that....
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #4 ·
This are the steps I did to try and fix the problem

1. Put in service mode by pressing start without touching brake.
2. I opened up gsd loade volt through vin
3. I went to Hybrid powertrain control module read all codes
4 I went back to menu clicked on erase codes clicked on dtc's and hit reset waited 45 seconds went back out and did the same for Hybrid powertrain control module 2.
5. I let the car go into sleep mode for 5 minutes then tried to start and nothing.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #5 ·
I also ran the coolant pumps one for the battery and one for the main system and made sure both were filled to coolant lines on both canisters.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #6 ·
I have a vcx nano and performed the procedure if this happens that I described above and tried several different times with no effect.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #7 ·
I have heard that sometimes the Hybrid powertrain control module 2 needs to be rewritten with new firmware. I have a subscription to one vehicle for 40 dollars from gm and like I said have the vcx nano I can use for the pass thru device. Has anyone heard of this fixing the problem because my volt is about ready to take flight off of a cliff.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #8 ·
It acts like its stuck in service mode, it will show the message of the volt with the spinning whatever you want to call it, i'm calling rather annoying but that's me pulling my hair out trying to solve the problem. I have went through the procedure for getting it out of service mode several times also.
 

·
Registered
Joined
·
192 Posts
Hpcm2 module has some errors that will clear only with reflash. Like the coolant level sensor

But I think at some version they enabled it to have (some more ) codes erased
 

·
Registered
Joined
·
405 Posts
My advice is to avoid changing any firmware unless you have documentation that doing so will address your problem as software doesn't wear out. Don't add another variable into your troubleshooting. The existing software was fine before the mechanical problem and will remain so, barring instructions otherwise to fixing the mechanical problem, after the repair.
 

·
Registered
Joined
·
13 Posts
Sounds like you know somewhat what you are doing, but not sure. I would find someone in here that knows more. Maybe they are not reading this blog anymore, but there are a couple of GM techs that come in every now and then. Reach out to them. And you can always suck it up and go to a dealership. The walk of shame. It might be a $400 fix.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #12 ·
The answer to this so anyone has this problem, is to reprogram the HPCM2 and all will be fine. I reprogrammed the hpcm2 and boom started right up. So I think I will keep my 400 dollars😁 and hopefully everyone that has this problem will to.
 

·
Registered
Joined
·
3,625 Posts
GM need to re-move the lock out state of the software so a re-load of the exact same software is not needed.
 

·
Registered
Joined
·
127 Posts
Two important things I noticed:
1. "My friend disconnected the msd while the 12 volt battery was still connected and so now neither the ice engine or electric engine will run". You used the word "so" indicating for sure this was the root cause. Correlation does not indicate causation, this could be a real issue somewhere besides related to the battery disconnect.
2. I am surprised no one asked the big question. You are getting a coolant isolation fault I see from the picture. You said you made sure the coolant was full. Did you add any coolant at any time during the whole repair? Was it the special GM deionized coolant made for electric cars?
 
1 - 15 of 15 Posts
Top