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Low voltage?

slowTA

By slowTA
in Troubleshooting & Recalls

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slowTA Enthusiast

slowTA

Posted
Posted

Today I noticed that my factory volt meter was showing well under 14 volts, very close to the bottom of the acceptable portion of the gauge, so I'm guessing just about 12 volts. After restarting the truck (which seemed normal) it went back up to 14 volts (straight up) for a few minutes and eventually backed down to 12 volts. Yesterday I took the truck for a 3 hour trip and didn't notice anything different.

 

Do these trucks have a funky alternator that disengages to save gas when not needed? I think I've read something about that somewhere.

 

The truck is a 2016, 5.3L, 8 speed, Z71 LTZ with about 1300 miles.

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

Normal. GM trucks have done this for a while now. Other brands may do it too but GM is one of the last to have "real" gauges that actually react to changes. I know on Ford trucks the gauges are basically idiot lights that read normal under a huge range of conditions.

Sierra 5.3 Enthusiast

Sierra 5.3

Posted
Posted

As long as your truck starts easily under normal conditions, no need to worry. It fluctuates. Watch the oil gauge when you mass on the gas. That's a fun one as well.

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted

Hello SlowTA,

 

I wanted to congratulate you on your recent Chevrolet Silverado purchase! We hope you enjoy your truck for many miles ahead. If you have any other questions or concerns, please don’t hesitate to reach out to us via private message.

 

Kindest regards,

 

Anthony J.

GM Customer Care

Today I noticed that my factory volt meter was showing well under 14 volts, very close to the bottom of the acceptable portion of the gauge, so I'm guessing just about 12 volts. After restarting the truck (which seemed normal) it went back up to 14 volts (straight up) for a few minutes and eventually backed down to 12 volts. Yesterday I took the truck for a 3 hour trip and didn't notice anything different.

 

Do these trucks have a funky alternator that disengages to save gas when not needed? I think I've read something about that somewhere.

 

The truck is a 2016, 5.3L, 8 speed, Z71 LTZ with about 1300 miles.

  • 2 weeks later...
redwngr Senior Enthusiast

redwngr

Posted
Posted
Battery Load Management


The vehicle has Electric Power Management (EPM), which estimates the battery's temperature and state of charge. It then adjusts the voltage for best performance and extended life of the battery.


When the battery's state of charge is low, the voltage is raised slightly to quickly bring the charge back up.


When the state of charge is high, the voltage is lowered slightly to prevent overcharging. The voltmeter gauge or the voltage display on the Driver Information Center (DIC), if equipped, may show the voltage moving up or down. This is normal. If there is a problem, an alert will be displayed.


The battery can be discharged at idle if the electrical loads are very high. This is true for all vehicles.

This is because the generator(alternator) may not be spinning fast enough at idle to produce all the power that is needed for very high electrical loads.

A high electrical load occurs when several of the following are on, such as: headlamps, high beams, fog lamps, rear window defogger, climate control fan at high speed,

heated seats, engine cooling fans, trailer loads, and loads plugged into accessory power outlets.

EPM works to prevent excessive discharge of the battery. It does this by balancing the generator's output and the vehicle's electrical needs. It can increase engine idle speed to generate more power, whenever needed. It can temporarily reduce the power demands of some accessories.


Normally, these actions occur in steps or levels, without being noticeable. In rare cases at the highest levels of corrective action, this action may be noticeable to the driver. If so, a DIC message might be displayed and it is recommended that the driver reduce the electrical loads as much as possible.

theatasigma Enthusiast

theatasigma

Posted
Posted

I have seen mine go from 12.5V to 15V all the time. Normally it stays around 14V.

  • 2 years later...
kennyc New Member

kennyc

Posted
Posted

so my 2015 gmc sierra voltage drops to like 11 about 40 seconds and starting I clean the battery terminal and now it hold like 14.5 I took I to my  Mechanic when it was reading 11 and side it wasnt charging I clean the terminals when I got home and its holding at 14 could it be the alternator 

g2full Enthusiast

g2full

Posted
Posted

They've used this system since 05 or so. But as everyone above me stated, it's normal... and it's designed that way. 

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