Charge System Fault
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Intermediate
Joined: Aug 2017
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Charge System Fault
I have poured over many posts related to this and am still lost. I received the charge system fault error after a track day and subsequently had my alt and battery tested. The alt failed 6 different times at two different test locations (AutoZone and O'Rilley's) and the battery tested "good" but needed a charge. I ended up ordering a reman AC Delco alternator and installed that along with the charged battery back on the car but the charge system fault continues to come up. I have cleaned the grounds and checked the connection at the starter solenoid which seems solid and there are no visible signs of corrosion/frayed wires.
The battery does only read 12.05 volts with a multi meter and this drops to 11.5 when the car is started. The DIC shows a similar voltage to this as well. To me this would indicate that the problem is somewhere between the alternator and the battery. Is this thinking correct? I am not sure if a new battery would help at this point but I am willing to try it I guess. Has anyone experienced something similar to this that might have an idea where the issue is?
The battery does only read 12.05 volts with a multi meter and this drops to 11.5 when the car is started. The DIC shows a similar voltage to this as well. To me this would indicate that the problem is somewhere between the alternator and the battery. Is this thinking correct? I am not sure if a new battery would help at this point but I am willing to try it I guess. Has anyone experienced something similar to this that might have an idea where the issue is?
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
If you still can get the old alternator back I'd do that and have it rebuilt !!...read the "sticky thread" in this Tech section called "Alternator Design and Issues"...will explain it all !!...easier than me or someone else explaining ad nauseam !!...12.05 volts open circuit testing is 50% charged...will the battery fully charge to 12.66 volts...what is the voltage across the battery terminals while running ???...take your volt meter and read from the B+ on the alternator to battery positive...what do you see ??...then take the volt meter from battery negative to the alternator case...what do you read ???
Cruising
Joined: Mar 2020
Posts: 10
Likes: 2
From: South Carolina
I would fully charge your battery.
When I bought my car, I was getting the DIC message. Read on here about getting a new "Voltage Regulator / Brush Assembly For Valeo 110A Alternators On: 1997-2002 Chevrolet Corvette , Fiat LCV - Europe"
10 minutes to install and took care of my issue. I make no guarantee about it fixing yours, but I went down the same path you did.
I agree with C5 Diag, read https://www.corvetteforum.com/forums...nd-issues.html
When I bought my car, I was getting the DIC message. Read on here about getting a new "Voltage Regulator / Brush Assembly For Valeo 110A Alternators On: 1997-2002 Chevrolet Corvette , Fiat LCV - Europe"
10 minutes to install and took care of my issue. I make no guarantee about it fixing yours, but I went down the same path you did.
I agree with C5 Diag, read https://www.corvetteforum.com/forums...nd-issues.html
Thread Starter
Intermediate
Joined: Aug 2017
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Thank you both. I did keep my alternator luckily so I'm going to work on getting that rebuilt and a fresh charge on the battery.
@C5 Diag - I must admit I am new to using a volt meter so I tried your suggestions but the readings were all over the place. I'm not sure the readings I got would mean much unfortunately.
@C5 Diag - I must admit I am new to using a volt meter so I tried your suggestions but the readings were all over the place. I'm not sure the readings I got would mean much unfortunately.
Melting Slicks
Joined: Jan 2009
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From: Miami FL
This other post has detailed info on the rebuild procedure and links to get the other parts.
Last edited by GCG; Jun 18, 2020 at 12:08 PM.
Thread Starter
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Dumb question but when testing from the battery to the alternator, should the car be on or off?
When the car is off the voltage measured at the alternator (positive wire connected to B+ and negative wire on alt case) is 12.05, I assume the is good?
I did have my OEM alternator rebuilt but my battery will not take a full charge. I am hoping a new battery solves this issue.
When the car is off the voltage measured at the alternator (positive wire connected to B+ and negative wire on alt case) is 12.05, I assume the is good?
I did have my OEM alternator rebuilt but my battery will not take a full charge. I am hoping a new battery solves this issue.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,621
Likes: 4,066
From: Cape Coral, Florida
Dumb question but when testing from the battery to the alternator, should the car be on or off?
When the car is off the voltage measured at the alternator (positive wire connected to B+ and negative wire on alt case) is 12.05, I assume the is good?
I did have my OEM alternator rebuilt but my battery will not take a full charge. I am hoping a new battery solves this issue.
When the car is off the voltage measured at the alternator (positive wire connected to B+ and negative wire on alt case) is 12.05, I assume the is good?
I did have my OEM alternator rebuilt but my battery will not take a full charge. I am hoping a new battery solves this issue.
Car must be running to do this voltage drop testing !!
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Moderator, Tech Contributor
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From: Cape Coral, Florida
However you had the leads connected if you switch the multimeter leads around you would see 3 volts and not -3 volts...you sure it’s not .3 ????...3.0 volts is way to much of a voltage drop. The B+ alternator cable goes down to the starter solenoid...the battery positive cable connects there also...might want to get underneath and check for corrosion and or loose terminals !!...if you connect the red lead of the multimeter to alternator B+ and negative lead to a good ground what do you read ??...you will be reading the alternator voltage.If you are reading 11.7 across battery terminals you should see 14.7 at alternator B+...11.7 + 3.0 equals 14.7 !!...the alternator B+ lead at the solenoid has a fusible link as you can see...that may be bad !!
Last edited by C5 Diag; Jun 22, 2020 at 05:35 PM.
Thread Starter
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I did the test again and switched the leads and this time I did get ~2.9 volts.
Additionally, when I connected the red lead of the multimeter to the B+ and the negative lead to a ground I get ~14.6 volts.
I assume this means there is a voltage drop between the alternator and the battery and it is most likely where the B+ lead connects at the starter solenoid??
Additionally, when I connected the red lead of the multimeter to the B+ and the negative lead to a ground I get ~14.6 volts.
I assume this means there is a voltage drop between the alternator and the battery and it is most likely where the B+ lead connects at the starter solenoid??
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
Yes, there is a voltage drop on that alternator wire or on the positive battery cable...to see where it lies you test each point down the wire...test the alternator stud to the terminal on the B+ wire...see what that reads...if good test from the terminal end on B+ to the terminal end on the alternator wire at the other end at the starter...then check terminal ends of both alternator and positive battery cable at starter....and then up to the positive battery terminal...you are just checking each section of wiring at each point to see where you have that excessive drop !!...if were to jumper the alternator B+ to the positive lead on the battery your battery would be charging normally !!
Last edited by C5 Diag; Jun 22, 2020 at 09:38 PM.