High voltage 2011 GMC Sierra

[Brett Helmeczi]

I bought a 2011 GMC Sierra just over a month ago from my dad and the volt meter on the dash is reading about 16. The alternator and battery were both changed in the spring. I put an LED taillight strip on a few weeks ago and I'm thinking it could possibly have something to do with that? When I was driving home for the holidays I got ago halfway and the check engine light came on but then went away later that night after it had been sitting for a while. When I was on my way back the light came back on and hasn’t went off. The command start also doesn’t work when the light is on. 

[BlancoSilverado]

You might want to check the actual voltage with a meter and not fully rely on the factory gauge (it might be wrong).

[dsr611]

The charging system on this generation of trucks/SUVs ('07 and up) only charges when needed (alternator doesn't supply a steady charge to the system as older vehicles do).  You'll see the voltage meter fluctuate (on my '10, I'd see it down around12v and up to around 16v).

 

I doubt the LED light strip is causing the voltage fluctuation and CEL to come on.

 

Need to get the codes read to see what is causing the CEL to come on.

 

2 hours ago, Brett Helmeczi said:

The command start also doesn’t work when the light is on.

If you're talking about the remote start, no, it will not start the vehicle if the CEL is on.