2011 traverse 3.6 charging issue

dla442

Well-Known Member
volt gage drops down and thenn ight pops on. new alt, new battery. intermittent problem. checking cables but how to test the voltage sensor? hoping no ecu problem etc. any sugestions on why this is happening? its always when the car is driven for a while then volts go from 14.5 to high 12's etc and wont budge
 

Mooseman

Moderator
Is this vehicle new to you? It could be normal. Most vehicles after 2006ish have a SARVC that will drop the charging voltage down to mid-12v when power demand is low, like after charging up the battery post startup. Both my Avy and TB will drop to mid-12v while cruising.
 
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dla442

dla442

Well-Known Member
its not charging at all now. just tested from alternator pole to ground and notta. p0625 is shown now with swrvice charging system message. its a new acdelco alternator, i just have a hard time thinking its defective within 24 hrs. the symtoms of low voltage happened before replacing it too. pcm?
 
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dla442

dla442

Well-Known Member
new battery too, cables ohms at zero. grounds from engine to body good. or thinking that voltage sensor on the positive cable that doesnt come off without clipping the cable
 

MRRSM

Lifetime VIP Supporter
ChrisFix conducts a pretty exhaustive Diagnostic Procedure for "How to Test The Alternator" with the SUV static and also when idling under an Electrical Load conditions using a Digital Volt-Ohm Meter hooked up to the Battery Terminals:

 
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dla442

dla442

Well-Known Member
what side of the connector to the alternator is positive or communicates with the PCM? Orange or the other color which is too dirty to tell
 

MRRSM

Lifetime VIP Supporter
The PCM is NOT directly connected to the Power Circuit between the Alternator and the Battery. The PCM monitors the Alternator thusly and communicates with the "fake" Voltimeter on the Dash Panel via Pulse Width Modulation (PWM) about the Alternator and Battery on that single gauge.

Exemplar of the GM Trailblazer Envoy Ranier Early Model PCMs:

PCM Connector #2 (GRAY), PIN #51, Wire Color (GRY), Circuit #23, Function: Generator Field Duty Cycle Signal:
 

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MRRSM

Lifetime VIP Supporter
The Positive Side of any Alternator or Generator is ALWAYS the sole, Isolated, Insulated Power Connector Wire (usually colored Red or Orange) attached with an eyelet end via a Fastener threaded onto a Copper Pole for (+) Voltage into the Alternator. There may also be a Secondary Voltage Regulator Signal Wire that will be smaller and is also Red in color... or there will be a 2-3 Wire Connector mating the Alternator Rectifier Circuit to that of the SUV Engine Harness Connector.

The Ground side of this Circuit always the Metal Case or Frame of the Alternator itself... hopefully bolted solidly to the Engine Block. The Negative (-) side of the Battery meets up with the Engine Block via the Heavy Black Grounding Cable bolted solidly along its flank.

All parts of the SUV Body and Frame of the vehicle are likewise behaving as a Common Ground and usually get electrically "Bonded" together; either by Welding or by fastened Braided Copper Wire "Bonding Straps" wherever needed to assure that this remains the case.

For more precise vehicle specific electrical information, download a Service Manual unique to your Year-Make & Model SUV from any Post showing @Mooseman's Signature Line showing the Links and refer to all Electrical Diagrams in the appropriate chapters.
 
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dla442

dla442

Well-Known Member
im going to try another alternator. the connection plug wires that goto the pcm have continuity. just hope its not the pcm😡. anyone know how to test the hall effect voltage sensor on the battery cable?
 
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dla442

dla442

Well-Known Member
lol..mrrsm your post just updated..read it. that chart woulda saved me an hour of testing each pin on the harness 👍👍. doesnt the pcm tell the alternator to engage etc according to demand? ill repost after a new unit put on. now im getting a #4 misfire and injector code...hoping due to a less that 12v battery
 
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dla442

dla442

Well-Known Member
The PCM is NOT directly connected to the Power Circuit between the Alternator and the Battery. The PCM monitors the Alternator thusly and communicates with the "fake" Voltimeter on the Dash Panel via Pulse Width Modulation (PWM) about the Alternator and Battery on that single gauge.

Exemplar of the GM Trailblazer Envoy Ranier Early Model PCMs:

PCM Connector #2 (GRAY), PIN #51, Wire Color (GRY), Circuit #23, Function: Generator Field Duty Cycle Signal:
i got a 2011 traverse👍
 

Mooseman

Moderator
To test the SARVC sensor, just unplug it. The alternator should act like a normal alternator. Failure rate on those is fairly low, never heard of one failing. I've had a bad rebuilt ACDelco alt and a new Remi. Never had an issue with new Chinese ones.
 

MRRSM

Lifetime VIP Supporter
One Special Caution...

I have seen a few Brand New Alternator installations done with 'Just a Little Bit TOO Much Enthusiasm..." where the Intrepid Mechanic was using WAY Too Much Torque when tightening down the Positive Cable Fastener onto the Copper (+) Pole of the Alternator and actually spun the Electrical Wiring Contact completely free and loose from the Wiring Internals of the Unit.

If you can grab the presently tight Copper Stud and Nut holding that Cable with a Pair of Pliers and *wiggle* it back and forth ...even the slightest... then the Pole may have physical damage internally and the Alternator will need to be replaced. These connections are invariably placed in hard to access positions and so they invite a tendency to use TOO Much Ooomph when assuring that the Positive Cable is installed firmly. Just a Word To The Wise...

About the Alternator "Getting Signals from the PCM..."


Actually, Thanks to Nikola Telsa, he created something BETTER than a Thomas Alva Edison's Clunky Direct Current Generator... It REALLY is an Alternator creating Alternating Current as its primary function by converting the power of the Crankshaft into the Electrical Field Energy which is restricted after that in flowing only One Way using (Hopefully) a Pair of Rectifiers.

The Electrical System in your vehicle Does NOT run on the Alternator... JUST the Electrical Output from The Battery...which, just like getting a Fresh Glass of Water from the Tap (Spigot)...The "Glass" must constantly be refilled afterwards to be useful for Drinking Water. The Alternator is NOT directly connected to the Electrical System...JUST the Battery which provides a MORE Stable Power Source to everything needing power in the Vehicle.

The Alternator behaves like the Water Spigot... Constantly re-supplying the Battery with a "Fresh Drink" of Electric Over-Charge around 14.X Volts and never depending upon the PCM for anything... JUST the Serpentine Belt to convert Mechanical Energy into Electrical Energy. The only concerns the PCM has with the Alternator is whether or not IT is "Pouring out The Drinking Water" .

The Circuit I described above is an Example showing that PCM receives an Output Signal coming from the Alternator allowing it to create alert the "Fake" Voltmeter Read-Outs on the Dashboard with an indication of the Field Strength of the Alternator. The Driver always need to know that the Voltage output is enough to keep the Battery replete with "Fresh Drinks".

Usually... the Voltage demand to "Refill the Drinking Water" is VERY HIGH just after the Battery Storage Amperage is Drained during Start Up... and then its demand on the Alternator is reduced after a while as soon as the "Drinks" have been restored into the Battery. As this happens ...you'll notice the Voltmeter will drop slightly to being in "The Middle" of the Gauge. THIS is Normal Alternator to Battery Behavior
 
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dla442

dla442

Well-Known Member
roger. didnt torque the piss outa the pole, just tight snuggly. im feeling like a bad alt. glad to hear the pcm wont fault the alternator. find out wed or thurs when i fix er. hoping just coincidence low volt battery causing a #4 misfire. i think i get her fixed and maybee dump it. been money pit in 3 months had it for my daughter. ac blew up only after 9 months where the stealership had replaced to compressor for previous owners. my mechanic said he got about half oz of oil out and it didnt expell out prior to seizing. the stealership didnt replace evap or condenser after that pump!!!
 

Mooseman

Moderator
i think i get her fixed and maybee dump it.
Not a bad idea. When my son was working as an apprentice in a stealership, he saw several of these for tranny replacements on warranty. I used to see a lot of them on the roads around here, not anymore. They must be winding up in scrap yards already.
 

linneje

Well-Known Member
roger. didnt torque the piss outa the pole, just tight snuggly. im feeling like a bad alt. glad to hear the pcm wont fault the alternator. find out wed or thurs when i fix er. hoping just coincidence low volt battery causing a #4 misfire. i think i get her fixed and maybee dump it. been money pit in 3 months had it for my daughter. ac blew up only after 9 months where the stealership had replaced to compressor for previous owners. my mechanic said he got about half oz of oil out and it didnt expell out prior to seizing. the stealership didnt replace evap or condenser after that pump!!!
Sorry for your problems. I also have a 2011 Traverse. Great driving vehicle, love the ride, handling and solid suspension. But it seems like I am always repairing something. Seriously. I too replaced the alternator (tough job, used a salvage one because I did not want to risk aftermarket), had air conditioning leaking (more than once), etc. etc. My 2003 Envoy I probably spent less than $1000 in the few years - I don't want to even total the amount for the Traverse. I feel your pain.
 
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dla442

dla442

Well-Known Member
update..been defeated. new alt installed. charging great but still #4 misfire injector inhnition communication codes. replaced coil, no go. turned back on, alt now dead and reduced engine power. somethings shorting out. local mechaincs wont touch. off to the stealership. 6k car owned 2 months cost ke 2400 bucks already. ill keep ya posted on yhe drama
 

Mooseman

Moderator
5 hours just for diagnostic? That's insane!
 
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dla442

dla442

Well-Known Member
find out. I'm already out $200 for an alternator cuz I can't bring it back again and say that it was defective. the stealership going to rape me on a new one. first time in my whole career of buying cars got a lemon from someone. electrical s*** is the worst
 
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dla442

dla442

Well-Known Member
i think thats pointing to a larger issue. i think the main harness has been accessed before. the sheath was unraveled and put back
 

MRRSM

Lifetime VIP Supporter
@m.mcmillen 's posted Electrical Diagram PDF s very revealing about the Battery Current Sensor sleeved on the Positive Power Cable just ahead of the (+) Battery Terminal. This is a replaceable component that also communicates with the BCM-PCM on the GMLAN High & Low Speed Network and thus, may also be subject to Failure. (See the attached image below)

If that unit is not alerting the Computer to the actual condition of the Battery Charge... the Alternator may not be refreshing the Battery Charge properly. Perhaps by replacing it, things might change for the better. It is available on RockAuto for around $20.00. This video shows a Battery R&R for a 2010 Traverse describing the layout of all this gear with a mention that it may be necessary to "Register" the New Battery on the Battery System Module using a Scan Tool in order to avoid Over-Charging or Under-Charging the New Battery and ruining it:


Battery Module Registration Video:

 

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