I am helping a friend with a 2005 C6. I am used to C5 electrical drain diagnostics with great sucess having worked on several C5s for friends. Their C6 apparently has a random battery draning issue which I am sure I can diagnosis once it "locks-in". In the interim, what is happening is that when the battery drains and they recharge (with the battery installed) the following happens. With everything "off", once the battery gets to some charge level the windows go down. Then when they get in the car and activate using the remote the radio comes on and the A/C comes on. I was able to replicate this by simply disconnecting a fully charged battery and reconnecting. Once again the windows rolled down and when the remote was activated the radio came on the A/C was on. And yes, I verified the radio and A/C were off before doing the battery disconnect. Anybody have any ideas? I don't have the wiring diagram to start diagnostics but will if necessary. Just wondered if anyone else has experienced this. I did this myself after just verifying the battery drain was within spec at only about 15 milliamps. Based on that, I dedicded there was not anything obviously amiss to cause these 3 things to occurr. Thanks, Sam

 

It might be 05 specific, my 06 does not do that after battery disconnect.

 

I have it happen when ever i disconnect my battery and reconnect my radio and ac comes on. I think it's just normal on the 05's

 

Thanks guys, hope some more chime in. Sounds like at least one car does 2 of the 3 things this one does. Sam

 

Now that's a friend! Hats off to you My Man. I'm encouraged to read that I'm not the only one just "twisted" enough to repeatedly dive into something like that for a friend.

As others have speculated, there were some issues primarily isolated to 2005's. The 2005 C6 I purchased new, and owned for over five years was built 8/05 so, many of the new model issues were corrected by the time it was built. However, it did have an intermittent drain bug from day one. I don't recall it ever doing what you describe but, one thing I do recall was reading about a GM campaign involving a re-flash in effort to corrects “dead battery syndrome”, AKA DBS. One area it was supposed to address was to shut the car's hard drive down when parked, which. I do not believe this was the entire cause but, I do know first-hand that it was a contributing factor. My car was considered to be unaffected by GM but, the hard drive still fired up randomly when parked.

I realize much of the information I am sharing is somewhat irrelevant but, if the C6 you're working on has never received a factory re-flash, it may be something worth considering. Especially if it's an early 2005. As an updated flash may address the issue you describe, and possibly others. If you haven't already, you may also consider doing some searches here on the forum to see if anything productive arises.

Best of luck!
Spark

 

Thanks Spark. I will go by the local dealership and ask/discuus with them about computer reflash. I will also find out when their car was built. Like you I like to be able to help friends since I can. I know I saved one C5 friend a $1000-$2000 dealership bill by solving his drain issues. This forum provides a great resource for problem solving. What did we do before the Internet and forums??????????

 

Admirable indeed Sam...

If you get curious about the vehicle build date before going to the dealer, just check the decal in the driver side door. It will provide you a close enough idea (e.g. 11/2010). However, your visit to the dealer should still prove plenty worthwhile. If you don't drive the car there, be sure to take them the VIN. The dealer should be able to provide you a fairly comprehensive report of any work performed by a GM dealer. Updated calibrations occur daily for things we never think or hear of so, it's likely that an update exists for this car.

What did we do before the Internet and forums?????????? We probably just worked a little harder to learn the fundamentals that we selflessly apply to assisting friends in need, right?

You're obviously an intelligent and capable guy who will bring the issue to resolve. But if you wouldn't mind, let us know how it goes at the dealer, and what you learn along the way.

Spark

 

Thanks again Spark. When I bought my C5 the local dealership was able to print out everything they(GM) did including a reflash for the CLB problem. I know it did not really "fix" the whole issue which I plan to do soon. Once I figure out what is going on with their C6 I will post the results. LOL Sam

Thanks goodness, on my Super Stock Hemi and Pantera all I need is a thin dime for gapping and and a couple of wrenches. At least with car computers, they really do provide a lot of diagnotic help. Still use a tube tester to keep my jukeboxes running. I love old technology becusre you can actually "see" how it works.