Voltage problem on a 06 C6.
Thread Starter
Cruising
Joined: Apr 2008
Posts: 12
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Voltage problem on a 06 C6.
The voltage is dipping below 12V at idle and causing the charge system service indicator to light up. The car has a supercharger installed but I don't know what manufacturer it's from. It also has a Pioneer AVIC-D3 installed in place of the factory radio but the rest of the factory Bose system is still in tact.
The dealer is trying to say that the aftermarket "accessories" on the car are drawing too much current and exceeding the output capabilities of the alternator. I think this is a bunch of bull because the only thing that's in there is the AVIC-D3 which may only draw minimal load over the factory head unit. The dealer tech tried to say that the supercharger also is a load which I also think is bull because the supercharger is a mechanically driven device so it should have no electrical load associated with it. I think it may be a pully issue but I don't know.
Can anybody possibly shed some light on this?
The dealer is trying to say that the aftermarket "accessories" on the car are drawing too much current and exceeding the output capabilities of the alternator. I think this is a bunch of bull because the only thing that's in there is the AVIC-D3 which may only draw minimal load over the factory head unit. The dealer tech tried to say that the supercharger also is a load which I also think is bull because the supercharger is a mechanically driven device so it should have no electrical load associated with it. I think it may be a pully issue but I don't know.
Can anybody possibly shed some light on this?
Last edited by HIS4; Apr 10, 2008 at 04:36 PM.
Le Mans Master
Joined: Aug 2000
Posts: 6,486
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From: Las Vegas NV
There's no way the head unit is drawing that much power, and as long as the S/C isn't dragging the idle speed down below spec, that should have no effect.
The other possibility (other than the obvious problems of a bad alternator or battery) is that underdrive pulleys were put on when the car was modded, causing the alternator to turn too slowly at idle.
The other possibility (other than the obvious problems of a bad alternator or battery) is that underdrive pulleys were put on when the car was modded, causing the alternator to turn too slowly at idle.
Thread Starter
Cruising
Joined: Apr 2008
Posts: 12
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There's no way the head unit is drawing that much power, and as long as the S/C isn't dragging the idle speed down below spec, that should have no effect.
The other possibility (other than the obvious problems of a bad alternator or battery) is that underdrive pulleys were put on when the car was modded, causing the alternator to turn too slowly at idle.
The other possibility (other than the obvious problems of a bad alternator or battery) is that underdrive pulleys were put on when the car was modded, causing the alternator to turn too slowly at idle.
Somba master
Joined: Mar 2005
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Cruise-In 7, 9 & 12 Veteran
Wounded Warrior Escort '11
St. Jude Donor '07-'08-'09-'10-'11
The "Service Charging System" warning has affected a number of forum member's cars. Those who have had underdrive pulleys installed, even with the idle raised to compensate, have had this. Also, people without underdrive pulleys have had it too. Alternators and batteries have been changed out with varying success. There may be something else involved, and there is supposed to be a TSB out.
GM
GM
Thread Starter
Cruising
Joined: Apr 2008
Posts: 12
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The "Service Charging System" warning has affected a number of forum member's cars. Those who have had underdrive pulleys installed, even with the idle raised to compensate, have had this. Also, people without underdrive pulleys have had it too. Alternators and batteries have been changed out with varying success. There may be something else involved, and there is supposed to be a TSB out.
GM
GM
Race Director
Joined: Dec 2007
Posts: 19,030
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From: Maumelle Arkansas
St. Jude Donor '13-'14-'15-'16-'17
Back to stock
Sounds like this is common problem with after market superchargers that require pulley changes.
Put the stock pulley and manifold back on and see if that solves the poroblem.
These cars are just too complicated to add something as complex as a supercharger. Even if it's a kit made just for this engine.
It's simply not GM's problem.
LJ
Put the stock pulley and manifold back on and see if that solves the poroblem.
These cars are just too complicated to add something as complex as a supercharger. Even if it's a kit made just for this engine.
It's simply not GM's problem.
LJ
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Melting Slicks
Joined: Apr 2002
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From: Dove Mountain, AZ
I do not have a supercharger, but I have had similar problems on my 04 C5 and my 05 C6. Both started doing that before the battery went TANGO UNIFORM. After a new battery everything was stable at just over 14 volts.
Have a load check done on the battery.
Have a load check done on the battery.
Heel & Toe
Joined: Apr 2008
Posts: 18
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From: Humble Texas
I do have the same problem but have a supercharger on my 07 C6. Chevy replaced one alternator which fixed it for a while but the problem came back. Second time around they handed me a TSB (#PIC4402A) which basically says:
Subject: Service Charging System Message P0621 DTC Stored
Model: 2007 Chevrolet Corvette (LS2 and LS7)
Some customers may comment of a Service Charging System, Service Electrical System and/or a Battery Voltage Low message on the DIC accompanied by DTC P0621 in the PCM. This may be a result of a shorted wire on the generator bracket or a cut in the stator winding that is caused from high engine RPM, usually because the engine hit the rev limiter. The internal fan is flexing and when it does flex, it comes in direct contact with the winding. A new generator may do the same thing if the engine is placed against the rev limiter.
So....there answer is don't hit the rev limiter or the alternator will be damaged....so much for there high performace offering....
Subject: Service Charging System Message P0621 DTC Stored
Model: 2007 Chevrolet Corvette (LS2 and LS7)
Some customers may comment of a Service Charging System, Service Electrical System and/or a Battery Voltage Low message on the DIC accompanied by DTC P0621 in the PCM. This may be a result of a shorted wire on the generator bracket or a cut in the stator winding that is caused from high engine RPM, usually because the engine hit the rev limiter. The internal fan is flexing and when it does flex, it comes in direct contact with the winding. A new generator may do the same thing if the engine is placed against the rev limiter.
So....there answer is don't hit the rev limiter or the alternator will be damaged....so much for there high performace offering....
