Help Me Understand

[1ed]

I have a 2013 Chevy Silverado Extended Cab with 5.3 engine with 77000 miles on it. I purchase this vehicle in April 2019.
I have driven it about 2000 miles and pulled my 23 trailer with no problems.
However, this Friday I noticed the Voltmeter was under 14 on the gauge and thought I might be having a alternator problem. After driving a couple of miles uo the road the gauge returned to plus 14. I did not change anything on the vehicle and it returned to what I consider normal or 14. I had a trip planned and since this is the first I have noticed this I thought It was better to cancel the trip until I determined exactly what if any was the problem. I put in a new interstate battery in November 2019. When i got home I checked the battery and it was 12.8 checked the alternator and it was 15.8. I let the truck sit for a few hours and checked the battery and it was still 12.8 checked the alternator and it was 15.8
Got the owners manual out and did not find anything that was informative on my situation.
Google different topic and found out on the SilveradoSirream.com web site that this is normal do to the economy mode system on the truck which has to do with the Fuel Magament System.

DOES ANYONE HAS A SITUATION WHERE THE VOLT GUAGE FLUCTUATES BETWEEN THE ONE ON THE 14 AND PLUS 14 ON THE GUAGE.

I Will be called the dealer in the am tomorrow. Thanks Ed

[jodeb720]

Mex is correct.

I had a 2003 silverado 6.0L - and charged, the voltage was just above 13 on my gauge (13.2 to be exact on my multimeter).

A couple of times, the battery got run pretty far down and the voltage was above 14 on my gauge - and I believe it was 14.4 to 14.6 during the initial charge - but never anywhere near 15.

GM's alternators are one wire - meaning the voltage regulator is built into the alternator. It sounds to me like the voltage regulator is going out.

Last Summer, My alternator went out on my chevy - due to not charging - and I replaced it on a depleted battery. It was at 14.5 or so on my gauge. I drove it for about 30 minutes and it was just a tad over 14.

josh

[time2roll]

MitchF150 wrote:
That's what a gauge is supposed to do.. Unlike the Ford ones which just sit at one position and is nothing more than a warning light..

What is to warn? Usually an alternator is working fine until it is not. If the gauge says normal I agree all is fine. Mine did register low once out in Wyoming. Pulled over at the next town and replaced it. Back to normal ever since with no reason to get in the dealer to check on fluctuations.

[time2roll]

I would be curious why the battery and alternator are not very close in voltage. Seems like an open circuit to me.

[MEXICOWANDERER]

Fifteen point eight is too high Drew

Northern California? 15.8 ?

It may be just the gauge.

Not worth the risk to guess at this. 16.0 volts will start damaging the chassis control module and the fact the ECU has not thrown a code is damning. love to see a LA battery that withstands 15.8 @ 70F which California has been enjoying.

Like being squashed in a packed elevator against a coughing feverish person.

Like the old Peanuts strip

CB My dad said our car started making funny noises coming home from work


Linus so what did he do?

CB. He turned up the radio

[DrewE]

According to GM's technical documentation on the subject, such as the one lawrosa linked above, the target output voltage in "charge mode" ranges between 13.9 and 15.5 volts depending on the battery state of charge and the estimated battery temperature. 15.8V actual doesn't sound too far out of line (particularly when made with measurement equipment of unknown precision).

[MEXICOWANDERER]

Help ME understand how a Delco Remy 145 amp alternator with Integral regulator is NORMAL showing almost 16-volts.

Ooooooooooo it can't hurt the battery
Ooooooooooo it's sone for the vehicle electricals

This is

NOT
NOT
NOT

NORMAL

Maybe the gauge maybe the regulator. The ONLY thing the ECU sees is the C connection of the alt which is an analysis of the ROTOR CURRENT

This will throw a ECU CODE

It ain't a Dodge and it ain't a Ford.

Recommendation
Take it to a genuine rebuilder shop and get it CORRECTLY DIAGNOSED


(16 VOLTS WE ITHOUT THROWING A CODE MY JACKASS)

[red31]

RVC

https://www.youtube.com/watch?v=8NRajpYXGb4

[ScottG]

14 is totally normal in a modern vehicle. If it's very cold it will be even higher than that and if it's hot, it will be lower.
No worries.

[Mike_LeClair]

Yup, I believe that GM uses the acronym "RCS" for Regulated Charge System" or somehthing along those lines. My 2006 Sierra 3500 does pretty much the same thing except I don't think that I have ever seen it as high as you are noting. I have seen it hit 15V under heavy operating load.

Cheers!

Mike

[theoldwizard1]

First, most dash mounted gauges are not very accurate.

Second, unlike older (pre-2000) vehicle, modern vehicles vary the charging voltage "as required". Using a "good quality" meter and measuring directly at the battery posts, typically the voltage will be above 14V shortly after starting, but will drop down to around 13.8V after it has been running for awhile.

If it drops below 13.2V at "fast idle", you have a problem !

[joebedford]

I have a 2011 Silverado with a Duramax. It starts at 12V and quickly (20 seconds) rises to 14V where it stays no matter what is going on. Original batteries.

My Harley OTOH would start at 12 and go to 17 and higher as revs went up. It was a fried voltage regulator. Replaced it and the battery as it was probably damaged from over-charging.

[wa8yxm]

14 is actually a tad high... But GM does like to run the system on the high side.. I will alarm one monitor I have at that voltage (I silenced he alarm the hard way) But based on your post I'd not worry. Sounds normal for a GM.

[owenssailor]

The GM trucks have a process to cut the field current in the alternator so they don't charge when the battery is full up and there is no other loads. This improves fleet fuel economy ratings. Nothing wrong. There was a tech bulletin on this.

[lawrosa]

rEAD PAGE 1 AND 3 HERE. GM HAS BEEN DOING IT SINCE 2004. mY ORIGINAL gm BATTERY IN MY 2006 SILVERADO LASTED 11 YEARS.

oops sry caps locked

https://srs20assets.service-solutions.com/Media/OEM/GM/en-US/Generic/Downloads/Document%20Library/TL...