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Discussion Starter #1
We have our Traverse for 2 weeks now and the volt meter had always stayed at the 15 mark. However, on the commute home yesterday and I noticed the volt meter dropped to below 13. It is my belief that alternator output should be around 13.5 to 14.5.

While I stopped for grocery and at the gas station, I observed (once after I started up the car) that the needle would start at 15 and gradually drop to below 13. I have a Scanguage II and it confirmed the OBD reading of 12.7-12.9.

This morning the car is doing the same thing so I pressed the onstar button and requested a full diagnostics report. I found out that onstar couldn't really troubleshoot for trouble unless there is a check-engine light or dash message... The onstar rep then offered to connect me to my dealership. I explained the problem to my dealership's service guy and he asked me what car I am driving. After hearing "Traverse" and he just said "that is normal and Traverse shuts off the alternator when it is not need".

So I kept on driving to work and for the next hour the voltage hoovered between 12.5 & 12.6. Toward the end of my commute, the voltage did go back to 13.5 for a brief moment but then dropped back to 12.7...

So is this a normal behavior with our Traverse alternator? My DRL and radio and fan all work and stayed on this morning. And I did measure the remote negative and positive terminals with a multi-meter, I got 13.1 v.
 

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I'm not positive about the Traverse and I haven't noticed it happening on ours. However, I drive a 2007 Chevrolet Avalanche and I've had the same thing happen. I contacted the service department and they assured me that it was normal. They even told me that it does it to save gas mileage. Said it saved 1%. So, it wouldn't surprise me to learn that the Traverse does the same. I don't get to drive ours enough as it is the wife's daily driver.
 

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lxc said:
This morning the car is doing the same thing so I pressed the onstar button and requested a full diagnostics report. I found out that onstar couldn't really troubleshoot for trouble unless there is a check-engine light or dash message... The onstar rep then offered to connect me to my dealership. I explained the problem to my dealership's service guy and he asked me what car I am driving. After hearing "Traverse" and he just said "that is normal and Traverse shuts off the alternator when it is not need".
According to what I recall reading in the owner's manual, the OnStar is supposed to run a diagnostics check once a month and email it to you...so as far as not checking it unless the trouble light is on, is a load of crap.

Medman
 

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One of onstars features- is that once a month it runs a diagnostic.
I dont recall it pointing anything out about alternators.... ill have to check it in a bit...

Also- it is my understanding-- that the newer cars- the computer can control the alternators output.
no need to pump out 15 volts if you dont need it.
it can control the output- and this mean the alternator is less of a load on the engine.. and in turn- higher mileage. like mentioned it may possibly be 1%... but every bit helps.

in the old days- you could revv an engine to 3 or 4000 to get the highest output out of the alternator...how many remember revving it and watchin their voltmeter go up... and then back down when it hit idle?

so yeah- im not surprissed you notice this. I think on some cars that voltmeter may be a little more sensitive than other cars....
 

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ok, just looked into my latest report.
it does have a tab for the electrical system.... all of mine came back ok.
I guess if theres an issue- the tab for the particular item becomes yellow or red... all of mine were green.
these are a few of the items checked. I didnt paste the rest.


Engine and/or Transmission System [—]

Diagnostic: Complete. No action needed.



Air Induction System [+]


Fuel Management System [+]


Engine Cooling System [+]


Throttle Control System [+]


Variable Valve Timing System (if equipped) [+]


Displacement on Demand™/Active Fuel Management System™ (if equipped) [+]


Ignition System [+]


Engine Electrical System, including the Charging and Starting System [+]

Engine Electrical System, including the Charging and Starting System [—]

The engine electrical system has several parts. The starting system uses an electric motor attached to the engine and is powered by the battery. In order to ensure that your vehicle starts, the vehicle battery needs to be continually charged. This is done using a device called a generator (or alternator). Once the engine is running, the generator creates electrical energy to recharge the battery. The generator and battery work together to supply the power to run the electronic features in your vehicle. In the event that one of the sensors in the system detects a problem, the engine computer can turn on the Check Engine/Service Engine Soon or Battery light to indicate a malfunction. That information can also be sent to your OnStar Vehicle Diagnostics check to alert you that service is needed.

Hybrid Powertrain System (if equipped) [+]


Transmission System [+]
 

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I have had mine almost two weeks and i noticed the same thing yesterday when i was driving it to work.
 

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Discussion Starter #7
I find this post on acadia forum http://www.acadiaforum.net/forum/index.php?topic=4895.0 that explains how the alternator works.

On my way home today, I purposely turned on the AC and radio volume at high. The volt meter remained at 1 mark below the 14. The alternator must be working and supplying enough amps...

The analog volt meter in our car is not accurate; 14 mark is really 13.5V (OBD port readout) and 1 mark below 14 is only 12.7-12.8.
 

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very informative link. thanks.
 

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lxc said:
I find this post on acadia forum http://www.acadiaforum.net/forum/index.php?topic=4895.0 that explains how the alternator works.

On my way home today, I purposely turned on the AC and radio volume at high. The volt meter remained at 1 mark below the 14. The alternator must be working and supplying enough amps...

The analog volt meter in our car is not accurate; 14 mark is really 13.5V (OBD port readout) and 1 mark below 14 is only 12.7-12.8.
Why can't salespeople have this information to give to the customers? It's things like this that build value in the product, and keep people from expecting that a vehicle have huge rebates, and discounts. When you read just what's involved in the electrical system, battery maintenance wise, it's amazing the technology. If every system in the Lambdas had details like this, that were given to the shopping customer, don't you think that would be something to help sales? I bet that less than 10% of salespeople even touch on explaining all that to the customer. (or, don't even know it themselves) I think there should be, maybe a little more abbreviated version, available with other literature at the dealer, that customers will actually see what they are paying for.
 

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I have had my Traverse about 60 days and it does the same thing. At times the voltmeter is below centerline then after the next start it is above then drops below. Sounds like this is normal as my battery has not run down.
 

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To All, while we were coming home from Stone Mountain I noticed that the voltage dropped down to 13v. I turned off all the acc and turned off the auto headlights. No change, then my wife said call on star since we were on the road and wanted to know what was going on. The On star rep ran a check and said it was ok. But since having an mechanical background I wanted more info. They connected me with there tech department. I was told that the computer controlls the alternator output and will shut it off when not needed. It shut off the current to the armature which stops the load on the alternator and thus the guage show a lower reading. I was told by them while driving that as long as it does not drop to 10v then it should be fine.

However on a diffrent note has anyone noticed if there acc plugs stop working. I was charging my cell phone last night and when I tried to check the plugs none of them were wooking.
 

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guapo said:
To All, while we were coming home from Stone Mountain I noticed that the voltage dropped down to 13v. I turned off all the acc and turned off the auto headlights. No change, then my wife said call on star since we were on the road and wanted to know what was going on. The On star rep ran a check and said it was ok. But since having an mechanical background I wanted more info. They connected me with there tech department. I was told that the computer controlls the alternator output and will shut it off when not needed. It shut off the current to the armature which stops the load on the alternator and thus the guage show a lower reading. I was told by them while driving that as long as it does not drop to 10v then it should be fine.

However on a diffrent note has anyone noticed if there acc plugs stop working. I was charging my cell phone last night and when I tried to check the plugs none of them were wooking.
Guapo, have you checked the fuses yet (for the acc. plugs)? Maybe something you plugged in caused a short or otherwise burned a fuse. Not likely, I know, but still the most likely reason.

On the alternator shut-off, that sounds great. Any part that gets less wear and tear when not needed is fine with me. But doesn't it seem odd it would "not be needed" if the lights, radio, climate control, etc. are on at the time???
 

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guapo said:
To All, while we were coming home from Stone Mountain I noticed that the voltage dropped down to 13v.  I turned off all the acc and turned off the auto headlights.  No change,  then my wife said call on star since we were on the road and wanted to know what was going on.  The On star rep ran a check and said it was ok.  But since having an mechanical background I wanted more info.  They connected me with there tech department.  I was told that the computer controlls the alternator output and will shut it off when not needed.  It shut off the current to the armature which stops the load on the alternator and thus the guage show a lower reading.  I was told by them while driving that as long as it does not drop to 10v then it should be fine.

However on a diffrent note has anyone noticed if there acc plugs stop working.  I was charging my cell phone last night and when I tried to check the plugs none of them were wooking. 
I bet Onstar and GM are kicking themselves for putting in a volt gauge.  They'll probably decontent that in the future, to avoid people calling them over nothing.  :happy:
 

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as it is.. some of the gauges-- are essentially dummy gauges.
they show approximate info... most people dont care...

Just like my 03 Trailblazer.. eventhough there are gauges there... most people dont look at them.
they dont understand the info.
Im not sure of the Traverse... but im sure its the same...as my Trailblazer... theres a light on the dash that says... CHECK GAUGES...
its supposed to illuminate when one of the gauges is showing pertinent info....
If youre really curious about the voltage-- plug into the OBD port- it shows the actual voltage. You need a scanner or scanner software for your laptop.
 

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I just got 2010 Traverse(3200km) back from the dealer for the same problem (gauge shows 13.2-14.1). The service guy told me its normally for the same reasons (gas mileage), I told him then why didn't it do it from the start? his answer was its still a virgin with that mileage, the computer is learning... go figure ...
So far I had to reroute the P/S line to cure a wining noise, Tranny update to fix jerking, seat belt recall , i hope thats it LOL
 

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Dman, actually, you're the only one with any of these problems. Kidding!!

As for the voltmeter, I don't know about why it would change from original readings, but, historically, my impression is that it can change from time to time depending on the charge of the battery and the demands placed on the charging system at the time, but that anything above 12 volts is acceptable for vehicle operations.

Anybody disagree with that?
 

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My 2010 voltage gauge shows me the same reading 13-14.5 volts , it's been like that since new .

Probable the voltage regulator is more sensitve than [/color]older[/color] alterntors a little bit more active . Just keep an eye on it to see if it dipps lower than 13 volts.
 

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Completely normal. The voltage on my drops too when driving on the highway for instance. I don't mind at all. I figure its all normal, otherwise you would get a battery light come on.
 

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Quantum said:
Completely normal. The voltage on my drops too when driving on the highway for instance. I don't mind at all. I figure its all normal, otherwise you would get a battery light come on.
Voltage regulation on the Traverse is handled through the computer. When the battery is "low" .... the readings will be high on the voltmeter, when the battery is "full" ....... the charge (alternator) is "shut off' by the computer, the voltmeter reading drops down. When the alternator is NOT charging, ...... less drag on the engine .... then mileage efficiency increases.

Bob
 

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I am a bit surprised that it isnt a dummy gauge. Many of us (me included :-[) did wonder why there seemed to be some wide fluctuation in the indicator needle. A dummy gauge would remedy this i.e. ignorance is bliss ;).
 
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