I've seen it three times in three days, Service Charging System. When I first start it up, then see the DIC message. I then see the analog battery voltage down around 12 or possibly less, touch the gas a little and it'll jump up to 13 and appears that it starts charging. I checked the battery cables as well as the alternator connector and the main feed wire out of it. Tomorrow morning I'll get under it and see if the starter battery cable is tight as well. The only last possibility is the original Delco battery is giving up suddenly but that's really unusual for the summer time. Its only a little more than 2.5 years old. Hopefully I'll make it home tonight from where I am at work, 60 miles away!

'07 Z51 3LT

 

It could be your battery. My original died at 22 months. It would help to have a load test done on it.

 

Do you have any mods? I could be your battery. Mine went 3 years so your getting pretty close to that.

 

No mods at all...totally stock. On my '99, the only time I ever saw this message was minutes before the positive battery post fell off the battery. Fortunately I was standing in front of it with the hood open when it happened. For it, I put in a Costco battery as that was the only place that was open way back then, for the day of the week and the time. That battery lasted for many years whereas the Delco one lasted only a couple of months.

 

I have had this problem come and go on my '06 A6 coupe. Two years ago I replaced the battery which did nothing. I replaced the alternator and problem solved. Last week it started doing it again, after I replaced the valve covers. Usually it happens shortly after startup and randomly as I drove around. The voltage drop would usually last only a few seconds. Rather than buy another alternator I swapped the one off my '08 Z track car. Interestingly, they are rated with the same voltage and amperage output and look identical but are different part numbers.

The problem still occurred with the "borrowed" alternator so I eventually switched them back. The wires going to the plug on the alternator I unwrapped and inspected and all are in good shape. I have checked the connections at the battery, alternator and starter and all are tight. I have followed the cables as far as I can to look for problems such as a pinch causing a short and found nothing. The one from the alternator disappears behind the back of the motor and is impossible to completely trace from above or below the car.

I drove the car about 30 miles today and it did not happen once. I was planning on ordering another alternator on Monday but maybe I'll wait and see. It's a wierd problem for sure and the sticky that addresses it is pretty inconclusive...

If you do decide to buy another alternator (or "generator" as it says on my GM invoice) the part number is 15841234 list was $463.43 although I got it for $266.47. That was in June 2007. It would be interesting to know if the part number is superceded by the one that came off my '08 Z.

Good luck and let us know what happens

 

Well, I put in a new battery this morning. Again, I checked all of the electrical connections and nothing was noted as abnormal. Coming in here to work, I only saw one small strange complication and that was exiting the freeway...on this long right circular turn off the freeway, I saw the digital battery voltage suddenly go up from 14.1, quickly going up to 14.4 and when I straightened out again, it went back down to 14.1. That's weird.

 

Happened to me...it was the connector on the altenator. It was corroded...had to pay for a new altenator.

 

12 volts is too low of an output. If you are seeing less around 12 volts while having no electrical loads on (winshield wipers, fans), then there is a possibility that you have an alternator issue. Delco batteries fail prematurely more often than not, even in the dead of summer. Does your car have any issue starting?

By the way, the "service charging system" light may not go off if there is a stored DTC (charging related) in the BCM.

 

You bring up an interesting point that I forgot to mention in my post. There were no DTC's set and no indication of a problem shown on the scan tool when the chime and DIC message came on.

 

hum. What module did you check? PCM? It will not show up in PCM/ECM, but in the body control module, something like a C0895. Many-a-times, I've had a healthy charging system, but the light will stay on in the IPC till that code is cleared.

 

I have 2005 still on original battery at 30,000+ miles.

 

No codes were set via checking with a hand-held scan tool. There are no issues starting the car only that I saw the voltage way below normal the couple of times which tripped the DIC warning and as quickly as I touched the gas, it went up and stayed up. I'll know more in the next couple of days but carrying the scan tool with me and DVM.

 

I would think the PCM/ECM, I plugged into the port under the steering wheel with a run-of-the mill auto parts scanner. I don't have a lot of experience extracting codes.

 

I would guess that this code is your problem. I can't find any GM info about the DTC, but i dealt with it just this week. There is a PI bulletin for that car regarding a damaged alternator after the vehicle has hit the rev limiter, but that will store DTC P0621 (may not be read/found by cheaper scan tools). I doubt that this is your issue.
Try this - it may not clear DTCs, but try taking both battery cables from the battery, hold them together for about 20 seconds (BATTERY UNHOOKED!!). Often times, if there is a confused module (logic-lock condition), this will correct it. Its a way of "starting at square one", so to speak.

 

Voltage IS dropping when the the chime/message comes on, but only for a few seconds then everything is back to normal. I think I am going to look into having the error code programmed out as suggested in another thread. Seems silly to buy a new alternator hoping it will solve an intermittent issue that isn't causing any problems other than the annoying recurrence of the chime/message. If it is the alternator it will permanently fail eventually and I don't go far from home these days if it does.

 

See my problem and resolution.

http://forums.corvetteforum.com/c6-t...esolution.html

You might consider some sort of intermittent short somewhere.

 

I did read your thread a few days ago, and while it is great information I have not had any problem with my horn and the message does not occur when the horn is used. I can't see any way that it could be related... Your thoughts?

I also looked for a short or loose connection by visually inspecting the battery, alternator, and starter cables. Part of the alternator cable disappears between the engine and firewall and cannot be entirely inspected from above or below the car.

 

What I'm seeing is when it first starts up, the analog gauge will sweep all the way up which is normal, then come back down to the lower voltage reading and instantly pop up to 13-14vdc. What it was doing is that sometimes it wouldn't pop back up till I touched the gas. Since I replaced the battery, it hasn't stayed down since, so far. I understand that the pcm or ecu is controlling the amount of charge from the alternator/generator which sort of points to either the alternator or the pcm being the cause. If my issue comes back, I have to wonder if either of those items are covered by the 5yr/100K warranty for the power train?

 

vetracer,
I wasn't necessarily suggesting that it might be your horn.

What I meant was that perhaps there is some other electrical item which has a direct (or near-direct) short. I realize this would be a real pain to trouble-shoot. But you might have to look at all aspects electrical... lights, heater fan, etc., etc.

In any event, I do wish you Good Luck.

 

I started having this issue after dragging on with a service active handling message and airbag lights coming on. I have replaced the battery, plugs, and wires. I can vouch that it can be coming from "somewhere else".

Taking it to another dealer this week. I will keep your posted, especialy if I change my alternator.

Rod