My gmc sierra hybird has a message that came up and said service hybird and will not start any help would be appreciated

 

Check 12V with load tester and check codes.

 

I put another 12v battery in it and still no start but there is no codes thanks for the reply

 

Unless you're using a professional grade code reader, there are a lot of hybrid system specific codes that your average consumer code reader can't check. If your car says "service hybrid system" as you indicated, then YOU HAVE CODES.

 

Welcome to the club of those who do not start Tahoe

 

I have had many problems out of this truck new transmission new lifters and cam and now the service hybird is on and will not start

 

You need to begin with data... codes

 

Sounds like you have had a LOT of wrenches turned on this vehicle.

I have had many problems out of this truck new transmission new lifters and cam and now the service hybird is on and will not start

I am not sure how recent the transmission work was? but if this were mine I would check the basic/easy stuff.
1. Pull the hybrid battery disconnect and reinstall it being 100% sure it is fully engaged and all 3 steps are done.
2. Do an underbody crawl and check ALL the electrical connectors that you can find especially around the transmission.
3. Check the hybrid battery voltage just for grins and giggles.
4. I guess at this point if I find nothing wrong I would call whomever (stealership?) did the other work to help with it?