Service charging system
Thread Starter
Race Director
Joined: Jul 2000
Posts: 16,481
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From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
2025 C8 Z06/7/E-Ray of the Year Finalist - Unmodified
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2020 C6 of the Year Finalist - Modified
Service charging system
I did a search but did not find a thread with a similar problem. Here's what I have going on:
Car is up to temperature and at idle in gear (A6). I'll get the three ding chime warning and "Service Charging System" message on the DIC. The voltage readout on the DIC is between 13.8V and 14.2V when it occurs I've been driving with the voltage display in the DIC so I can monitor what it's reading when the warning goes off.
The battery is an Optima yellow top that's a little over a year old. It has been load tested and checks good. My alternator is putting out the correct charge as well. I have not looked at the starter connections and I have not had any issues with start up whether the car is cold or hot.
I do have long tube headers and a supercharger. This has been intermittent for about two weeks and does not occur every time I drive it. My car does sit up to four days without starting at times.
Any insight as to what may be the cause is greatly appreciated. I do my own maintenance and the warranty has expired. It's an 06 with 16K miles.
Car is up to temperature and at idle in gear (A6). I'll get the three ding chime warning and "Service Charging System" message on the DIC. The voltage readout on the DIC is between 13.8V and 14.2V when it occurs I've been driving with the voltage display in the DIC so I can monitor what it's reading when the warning goes off.
The battery is an Optima yellow top that's a little over a year old. It has been load tested and checks good. My alternator is putting out the correct charge as well. I have not looked at the starter connections and I have not had any issues with start up whether the car is cold or hot.
I do have long tube headers and a supercharger. This has been intermittent for about two weeks and does not occur every time I drive it. My car does sit up to four days without starting at times.
Any insight as to what may be the cause is greatly appreciated. I do my own maintenance and the warranty has expired. It's an 06 with 16K miles.
Burning Brakes
Joined: Feb 2008
Posts: 988
Likes: 2
If the alternator is overdriven it could fry. Mine did about an hour after I put in the cam and hit my raised 7000 rpm redline a couple times. Thats my only experience with the alternator failing.
(Installed a Z06 alternator to correct it)
(Installed a Z06 alternator to correct it)
Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10
You need to check it out.
The voltage display in the dash is not the only place it is being monitored.
If the ECM sees a difference out of the range of parameters it will generate the error. You can start by doing a voltage check with a good DVM at various places such as the ALT TERMINAL , BAT TERMINAL and be sure your grounds are good. May be a good idea to check those voltages
and clean the B+ Terminals, ALT, Fuse box STARTER and Grounds.
If the ECM sees a difference out of the range of parameters it will generate the error. You can start by doing a voltage check with a good DVM at various places such as the ALT TERMINAL , BAT TERMINAL and be sure your grounds are good. May be a good idea to check those voltages
and clean the B+ Terminals, ALT, Fuse box STARTER and Grounds.
Racer
Joined: Dec 2007
Posts: 413
Likes: 0
From: Bradenton Fl
I ran into this issue three times. (07 A6 with stroked ls2 an supercharger). First time I took it to GM, and they said it was the battery so they replaced it under warranty. Two days later it popped up again, took it back in. This time they replaced the alternator. As Im leaving the lot ding, SCS again..reverse back into service.
What seem to have solved the issue was they took a piece of 8g power wire usually used in stereo systems, and ran it from the back of the alternator to the fuse box terminal (the post off to the side to add-on power wires). Ever since then, I have not seen that message pop back up.
Also ended up going with a aftermarket 230amp alt because with florida heat, and the heat from the s/c and motor..it was overheating the alt. itself, still use the power wire trick though.
What seem to have solved the issue was they took a piece of 8g power wire usually used in stereo systems, and ran it from the back of the alternator to the fuse box terminal (the post off to the side to add-on power wires). Ever since then, I have not seen that message pop back up.
Also ended up going with a aftermarket 230amp alt because with florida heat, and the heat from the s/c and motor..it was overheating the alt. itself, still use the power wire trick though.
Heel & Toe
Joined: Sep 2008
Posts: 22
Likes: 0
From: MIAMI FL
I am having the same issue i also have 06 a6 supercharged. It will charge same as yours but if it idles you could see the gauge moving up & down and the service charging will come up until i go up on the rpm. My idle is at 750 so its not that low.
Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10
I ran into this issue three times. (07 A6 with stroked ls2 an supercharger). First time I took it to GM, and they said it was the battery so they replaced it under warranty. Two days later it popped up again, took it back in. This time they replaced the alternator. As Im leaving the lot ding, SCS again..reverse back into service.
What seem to have solved the issue was they took a piece of 8g power wire usually used in stereo systems, and ran it from the back of the alternator to the fuse box terminal (the post off to the side to add-on power wires). Ever since then, I have not seen that message pop back up.
Also ended up going with a aftermarket 230amp alt because with florida heat, and the heat from the s/c and motor..it was overheating the alt. itself, still use the power wire trick though.
What seem to have solved the issue was they took a piece of 8g power wire usually used in stereo systems, and ran it from the back of the alternator to the fuse box terminal (the post off to the side to add-on power wires). Ever since then, I have not seen that message pop back up.
Also ended up going with a aftermarket 230amp alt because with florida heat, and the heat from the s/c and motor..it was overheating the alt. itself, still use the power wire trick though.
ALT SENSE CKT considering the additional load the SC would demand in current . Kind of slick but I can see how it would do the trick. Its pitiful
how these techs just change the battery then the alternator and actually the next thing they would do is change the ECM . Thats kind of what the shop manual tells them if they are not trained to use the electronic tools available to measure , monitor and diagnose.
Racer
Joined: Dec 2007
Posts: 413
Likes: 0
From: Bradenton Fl
Well not to long after that, I kinda got forced to drive through a puddle a little deeper then expected (came up to the bottom side of the bumper)...but the splash was big enough to some how hit my ECM. Two seconds after the puddle my car started acting funny. Took it to the shop who built my motor and said water had found its way an was all over the terminals. Had the car taken to the dealer, they said the same thing...but they decided to not warranty it saying that my spark plugs were sending RF interference and messing with the ECM (I am not pulling this out of my *** either, Ive got the sheet somewhere saying that). They told me that I was running pulse technology plugs in a car not made to handle them (I was running NGK Vsparks )..when I asked them what brand plugs I was using they wouldnt give me an answer. When I spoke up they got the service manager, they talked and voided the rest of my car warranty.
Needless to say I took it back to the other shop, who took it out, cleaned the terminals off, then took care of it so they wouldnt get wet again. Not a problem since. Im sure with the new alternator I could take the wire off, but its there and Im lazy.
Needless to say I took it back to the other shop, who took it out, cleaned the terminals off, then took care of it so they wouldnt get wet again. Not a problem since. Im sure with the new alternator I could take the wire off, but its there and Im lazy.
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Melting Slicks
Joined: Sep 2007
Posts: 2,597
Likes: 3
From: READING PA
St. Jude Donor '08-'09-'10
Well not to long after that, I kinda got forced to drive through a puddle a little deeper then expected (came up to the bottom side of the bumper)...but the splash was big enough to some how hit my ECM. Two seconds after the puddle my car started acting funny. Took it to the shop who built my motor and said water had found its way an was all over the terminals. Had the car taken to the dealer, they said the same thing...but they decided to not warranty it saying that my spark plugs were sending RF interference and messing with the ECM (I am not pulling this out of my *** either, Ive got the sheet somewhere saying that). They told me that I was running pulse technology plugs in a car not made to handle them (I was running NGK Vsparks )..when I asked them what brand plugs I was using they wouldnt give me an answer. When I spoke up they got the service manager, they talked and voided the rest of my car warranty.
Needless to say I took it back to the other shop, who took it out, cleaned the terminals off, then took care of it so they wouldnt get wet again. Not a problem since. Im sure with the new alternator I could take the wire off, but its there and Im lazy.
Needless to say I took it back to the other shop, who took it out, cleaned the terminals off, then took care of it so they wouldnt get wet again. Not a problem since. Im sure with the new alternator I could take the wire off, but its there and Im lazy.
was driving me nuts. In the future when our warrinties go out we are on our own. Sorry I got off here and forgot about the Op. I apologize.
I think the Op should get a piece of 8 ga stranded wire at home depot
and some heavy ternimals at auto zone. Crimp the ends and mount it.
It would be the test of the alt sense line if the problem goes away. I wish he were here I really have the stuff to find out whats wrong rather
than cover it up.
