Good afternoon.

I’m at a loss right now for my service charging system message. I absolutely hate these messages otherwise I’d leave it.

The first thing i have replaced the alternator with a duralast from autozone. The original ended up testing good but the volts were going between 11-14 volts at idle. After replacing the alternator (Duralast) I’m at solid 13-14v BUT …..I’m still getting the dang message. I replaced the battery and still got the message, so I returned the new battery cause the previous one was 100% charged and no issues with it. I have not replaced the starter, but I checked the ground from looking above with a 13mm and made sure the connections were tight and secure. I’m really getting annoyed with this error message. It seemed to come on right after i replaced the 20amp fuse for the cigarette lighter under the passenger side. I checked the horn/alt fuse under the hood and heck i even replaced it. Nothing, error pops right back up so I’m literally confused now as what it could be, maybe a ground somewhere. Might need to drop er off at the dealership. Had the computer reset, had the computer scanned, no codes…. Any suggestions would be WONDERFUL.. stupid charging system lol


mods:
BTR stage 2 cam
Long tube headers
xpipe
stage 2 tune.
MGW short throw shifter

i installed a MSD 2 step and it works great, i tapped into a unused plug plug that was in the center console but was unused (magnetic ride control) but mine does not have it. So i tapped into the 12v wire for a switch for a MSD launch control on/off switch. It works great and don’t think this issue is contributing to the message on the dash. But maybe there is a ground around this area i did not tighten

 

First step.......begin to disconnect, one at a time, those every things that you have installed and see if the code disappears, if so then you may have a ground fault somewhere.

 

Disconnected the MSD 2 step. Started still showed up. I checked every fuse in both panels. I pulled out the fuse from the cigarette lighter (i replaced it) and still shows up. Not sure where to go from here besides replacing the starter or dropping it off at the dealer.

 

There’s been a number of posts about problems with non-OEM alternators that turn out to be incompatible with the charging control circuit. Maybe @Dano523 will chime in on the details, because it sounds like this could be one of those cases.

 

Did you check BOTH sides of the fuse 2 with a 12 volt test light ??...horn works ??...you may want to check for 12 volts at the red/white wire at the alternator connector and can be done engine OFF...it is the wire closest to the engine...if no 12 volts you may have an open in the wire between the fuse and the alternator connector...this is not a starter issue and if you take it to a dealer they will replace your alternator again and maybe a few other items like an ECM...also check that connector...and BTW welcome to the Forum...it's a good idea to fill out your profile...model year and whatever else you want to include

 

im starting to think that, because before the car would only show the light ONLY when it dipped down below 12volts with the OEM. Where now it displays it as soon as I turn on the car. But the actual volts are 14+ now..with the aftermarket one. I’d hate to pay to get another one but I guess i can always return it.

 

i have not did the fuse 12v test. Horn works. Thanks for the welcome I’m glad to be a vette owner again. Just trying to get this issue resolved and I’ll be a happy camper again. She runs good I’ll fill out my profile asap. I’ve seen a lot of people say the starter ground solenoid fixed the same issue. But i don’t think it’s my case since I can look directly at the ground through the headers.

 

If the charging system reads a steady 13-14 volts running you don’t have solenoid issue…and it’s not a “ground”…the alternator B+ and the positive battery cable are connected together at the solenoid…”looking” isn’t the right way to diagnose this…you have to physically get down there and check…if this is over your head I’d take your car to an auto-electric shop and not a dealership.

 

i got a 13mm and physically tightened the bolt holding the ground and the solenoid on the starter. It didn’t have any play. Not over my head, but running out of options to try which is why I’m seeking advice on here.

 

I’d check for 12 volts at the alternator connector red/white wire.

 

Looks like we’re good there

 

Well just because your Duralast alternator is new doesn’t mean it’s good or perhaps the right part number…I’d bite the bullet and head down to your local GM dealership and get yourself an OEM alternator but first how about putting a load on the alternator such as high beams, AC, defogger, seat heaters and see what your charging voltage is taken at the battery…I’d be checking the alternator duty cycle with a scope with various loads on the alternator but doubtful you have one of those…some scan tools can also read this duty cycle…what year is the car ??

 

i have a GM mechanic at Chevy that’s going to diagnose it for me tomorrow. I had both alternators tested at autozone yesterday. The one i replaced tested good but i had already swapped with the new one, but i wanted to go ahead and keep the new one just In case the regulator was not working. It may just be that it’s not OEM and doesn’t work with the charging system. I guess I’ll figure out tomorrow. I’ll definitely keep everyone updated on here to help out another vette owner with the fix.

 

GM mechanics usually fall short in the diagnostic arena and some parts like this are better being purchased at a dealer…this way you’ll be getting the correct part and usually a good one…good luck !!

 

yeah. I have the receipt for the autozone alternator if that ends up being it, but that may be overlooked considering it’s testing fine….I’ll be so butt hurt if this whole time it was just the Duralast brand vs OEM and just not working with the charging system. Maybe we will see. If he can’t figure it out tomorrow I will just go ahead and swap the aftermarket out for OEM.

Until then, here is my C6.

 

This is what I recall from several posts - YMMV. The OEM Valeo alternator does not have a voltage regulator. Voltage is monitored by the ECM, so the duty cycle of the alternator is controlled by the ECM by way of one of the wires in the circuit connecting to the alternator. Even though some aftermarket alternators might plug in electrically, they operate in a different fashion, and the ECM can't control them, so you end up with the message that you got. Once again, from memory, a C5 alternator will bolt up and connect, but you end up with the same fault because their voltage output is controlled differently.

 

Lets state with the valeo alternator body for the C5 and the C6, are the same unit,

But,

C6 alternator voltage regulator connector,


C5 alternator voltage regulator connector,


Being that the rebuilt Duralast alternator has the one way pulley on it, that is only used for the Auto transmission models,but they are pushing it for the manual trans as well, guess which voltage regulator it may have in play as well.
Hence the reason that the unit is causing problems on the C6, its the wrong voltage regulator in play on the unit to start with.

 

this was a super helpful illustration. Chevy tech diagnostic came back with nothing wrong. The next step on the sheet is to replace the Alternator. GM near me is on back order for an OEM alternator and it’s $900. I found a Valeo one on Amazon for $311 shipped.

https://amzn.to/46dr5Fo


will be here in a couple of days. I’ll update back once the Valeo brand has been installed.

 

Buying parts like this on Amazon is sketchy...most likely a reman and whether it will work is hit or miss.

 

I hope not lol