Electrical issues

[Deputydog]

My 2009 Avalanche has some gremlins. First to
E the door locks went crazy and later the engine started missing. A mechanic at work told me to disconnect the battery terminals and touch them together to reset ECU. That worked. Then on a long road trip during the heat of summer it did it again, this time I noticed my voltage meter dropped from 14 to 12. Any help on this??

 

[zora]

You need the charging system checked along with the battery if you show only 12v.
Do you have a check engine light on?

 

[Deputydog]

You need the charging system checked along with the battery if you show only 12v.
Do you have a check engine light on?

I do but the code is for the fuel tank pressure system. The 12 volts is intermittent and when it drops is when I have the issues

 

[zora]

Ok, so you have a charging system/battery issue and need to load test the battery and run tests on the charging system.