Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

High voltage 2011 GMC Sierra

Recommended Posts

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. 

Link to comment
Share on other sites

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. 

Screenshot_2019-12-30 Owner's Manual - 2011_gmc_sierra_owner pdf.png

Screenshot_2019-12-30 Owner's Manual - 2011_gmc_sierra_owner pdf(1).png

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.