C5-BRUCE

[I published this in the General Section near the end of a very long thread on the DBS issue. Thought it would be of benefit to post it here as well]

Sometime ago Jeff and I asked for information regarding your DBS problem, that we would forward it to the GM team working on the solution. As a result, several C6 owners were put in direct contact with our source and have been working with GM to identify the root cause. A number of you have suggested that GM is wearing blinders, which is not the case.

I received the following letter from our "Friend in High Places" which provides an update as to GM's efforts in trying to determine the cause and provide a fix. It is addressed to those of us who have been in direct contact. You are NOT being left out in the cold by GM!

Our source asks a question of us at the bottom of his letter. Please reply to me with any input and I'll see that he gets all responses: c5bruce@adelphia.net

Hello Everyone: I'm sure most of you do not know each other but you are all Corvette enthusiast that I have been communicating with regarding your dead battery syndrome. I just wanted to give everyone an update so you know where we stand. I was off on vacation in November and December but rest assured the project is moving forward.

There is a complete team working the issue and a specialist in root cause analysis has also been assigned. We have been successful in identifying
some issues that are not causing the condition and we also believe that it can not all be associated with customers not putting the car in reverse. Especially with this group I trust you all fully understand and practice the proper shut down procedures.

As you know for 2006 the shift to reverse feature was eliminated. GM was successful in convincing the Federal Government that this feature was not
essential in preventing car theft. While the Fed ruled GM could discontinue it on future models it did not approve a retrofit that would eliminate the requirement for 2005 models. So 2005 cars are stuck with it.

Also for 2006 the column lock feature has been removed. We are not sure how much, if any, this influences DBS but it is a difference we are investigating.

We understand there are two switches that are used to tell the BCM the shifter is placed in reverse. If these switches are not activated the BCM does not actually shut down the electrical system. The car could believe it is not in reverse and stays live, even when the shifter is in reverse.

We are developing a couple of testers that can easily be installed in a customer car and monitor these circuit and switches. We will be installing it in one customer car next week. We have had two test
computers built that are currently on customer cars that actually monitor battery voltage, amp draw and ignition cycles every 30 seconds. The computer is not invasive and the customer can drive the car while it stays connected and monitors the data. We are looking to our engineering group for more improvements that can determine if a module is not going to sleep as it is intended and identify the naughty module.

We are also looking at stray radio waves that could be waking up the BCM once it is asleep much like doing an key fob button press. In one case we identified a customer's car that lived close to the security gate for their neighborhood. Every time someone hit the button to open their security gate their car would wake up and go through the 20 minute shut down
procedure.

Each of you have been supplying information and data particular to your car and some of your friends. I thank you for your continued support and patience. We are making progress but since I have no idea how long the road is, I can only tell you when we can finish the race. Rest assured we will not quit until we identify the issue and correct it. As more information becomes available I will pass it to you.

If you are still driving your cars and don't happen to be hampered by Michigan's winter and bad roads, you could try something for me. As you drive and park the car and shift to reverse, once the car is in reverse do you ever get the message to shift to reverse even though it is there? Just curious. If you do experience this event please let me know.


Have a great January, enjoy the Detroit Auto Show if you are coming this way.

StanNH

Thank you very much for all your efforts, Bruce.

C5-BRUCE

Thank YOU Stan! And thanks for the input you sent me, I passed it along yesterday.

I know it's been frustrating for owners with the problem to not know what's been going on in the background. I hope the GM letter helps them to understand they are not being ignored, that GM is aware of the problem, has allocated resources and is working hard to resolve the issue.

Although I don't own a C6, I'm also in the "frustration pool". My C5's gas gauge dropped to empty again last Sunday - after SIX sender/sensor replacements! I'm beginning to think there should be an RPO option code for the Frustration Option, at no charge of course

scrannel

Thanks you guys. Great of you to try to solve this weird issue. Sure everyone on the forum feels the same.

VET4LES

It has not happened to me yet but I am glad to hear someone is working on the problem.

Madd_Matt

Can't thank you enough Bruce! I have only had one intance of DBS, but it was unusual in itself. Car was left in 5th - not reverse, BUT I NEVER GOT THE "SHIFT TO REVERSE" MESSAGE!

Rick Kasick

Went thruogh a series of DBS when I stored the car (stick). Removed the negative cable and five days later "no start". Don't know if that helps you. Had one good day of weather in NW Indiana and went to the dealer. Battery was replaced but there wasn't a dead cell which I expected. Technician said to put a trickle charger on it or remove the battery which I did. FYI - every time I took the original battery out and brought it home to charge, it had12.2 volts in it. Charging the battery brought it to 12.8 volts which started the car. I recently posted a message asking why we were all buying batteries for our $50,000 cars? I beleive the stock battery has to be upgraded as a start. Never experienced the "put in reverse" issue.

Thank you for your efforts.

ttomczak

I too thank both of you for your efforts...

I have had DBS twice, once about 6 months ago and then just last week.

Normally the car does not sit much, but it did for 2 days and I did not do my usual of putting my battery tender on it...

Boom DBS...

DJackman

Thanks Bruce.. Great post. I can breath easier now.
About the "shift to reverse"mssg, I didnt happen to me yet I hope.

capevettes

Thank you very much for that update. I'm glad they are working on this. I had several incidents of DBS, but none since last May. I'll be very interested in what they come up with. I'm convinced it's in the steering column lock mechanism. I was having DBS with great regularity until I began locking the column on my 6 speed. I don't believe it's a coincidence.

StanNH

Yet many of us who have experienced DBS have had the locks firmly engaged at shutdown. It may be related, but only in the sense that something in that monitoring circuit is misfiring. I don't think the actual position of the lock has any direct relationship to DBS.

As an example, for the first 10 months of ownership, I never checked my steering column lock and never experienced DBS. After reading all the posts about it on the board, I started locking it whenever I shut off the car. At 13 months I had my DBS incident ... with the column locked and the car in reverse. I think the only conclusion that can be reached is that no conclusion can be reached. What a PITA!

67Roadster

Thanks for all of your efforts Bruce, good to know that GM is on top of it

LTC Z06

Copied to C6 Z06 section and added to the FAQ.

MyRedC6

"As you drive and park the car and shift to reverse, once the car is in reverse do you ever get the message to shift to reverse even though it is there? Just curious. If you do experience this event please let me know"

This has happened twice in the two months I have owned the car.

mikeyc6

Thanks for the info! This really makes me feel better that GM is doing something about the problem. I had something happen today that I thought was rather curious as it may apply to DBS. I was driving today with the DIC set to display battery voltage. Since I had installed a Predator tune, I was using the battery voltage as a quickie indicator of how much power was being used by the engine cooling fan at idle (lower voltage generally indicates higher fan power). Anyway, I made a half dozen stops and noticed that every time I started it back up, the battery voltage at idle right after startup was always 13.9 to 14.0 volts. My last stop was at Arby's and I went inside for no longer than 10 minutes to get food to take out. I noticed when I turned the car off that the column lock "zip" sound sounded a bit short/weak but I chalked it up to me just playing the radio a little louder than usual so maybe I didn't hear it.

10 minutes later when I started it up again, I did my usual two taps on the AH/TC button and then a press on "Reset" to clear the "Competition Mode" message and right before (or right after, it happened so fast), I saw "Service Column Lock". My press of the reset button must have cleared it, but I always watch for messages there and I have never once seen "Service Column Lock", not even the one prior time I had DBS. Anyway, everything cleared and operated normally except I looked down at the battery voltage and where it had bounced between 13.9 and 14.0 on every prior startup, this time it bounced between 13.7 and 13.8. Could this be an indication that the column lock had fouled up and was drawing the battery down while I was inside Arby's? I checked the coolant temp immediately and it showed what it had showed every other time I started it up: 199 degrees.

As I said, I stopped at least 6 times, once not 1 mile down the road and every single time I started the car and let it idle right after startup, it showed 13.9 to 14.0 volts and somewhere between 199 and 203 degrees on coolant temp. Now I get this "Service Column Lock" message and all of a sudden, after that, it is showing a .2 volt drop? I know that ain't a big difference, but the sound of the column lock, followed by the "Service Column Lock" message, followed by the slightly lower voltage, and I'm putting my money on column lock as the culprit for DBS (or whatever circuit(s) drive it). One final note, I always jiggle the steering wheel to make the pin pop in place after I shut down and even though the CL sound might have been a little different this time and I did get that message, the steering wheel did lock as usual. That's why I brushed it off as maybe me just not hearing it over the MP3 CD I was playing.

Another clue in the mystery maybe? I never would have noticed anything other than the "Service Column Lock" message if I hadn't been playing with the cooling fan adjustment on the predator and watching the battery voltage and coolant temp all day.

Mike

shopdog

I'm not real happy with the way the alternator is managed on these cars. As some of you may know, our cars don't use a conventional voltage regulator to control the alternator. Instead, the ECM controls the alternator, regulating charge, and at times will completely shut it down while the engine is running. While in itself this is not alarming, I have seen cases where the battery isn't fully recharged after a drive. It should be, any drive over 10 minutes should fully replace the energy used to start the car. But I've seen battery voltages as low as 12.2 volts after a 10 minute drive, starting with a fully charged battery. Not good.

Put another way, there are cases when the alternator doesn't fully recharge the battery. So you wind up stopping with a partially depleted battery. Then when you go to restart, battery voltage may sag so low it causes the computers to freak out.

In a car with a conventional alternator and regulator, I expect to see system voltage around 14.2 volts after starting the car. That's the alternator busily stuffing charge back into the battery, which requires a voltage higher than battery voltage to do. Then after a few minutes, I expect to see system voltage settle to 13.8 volts, which is the float charge value for a healthy fully charged battery. I do not expect to see the voltage read 12.2 volts, but I often do in my car when idling at a traffic light. That tells me the battery isn't being fully recharged.

What does this have to do with DBS? Probably nothing, but if you start out with a partially discharged battery, it is a whole lot shorter trip to a dead one.

StanNH

If it did have some impact on DBS, wouldn't it affect both manual and automatic transmission cars the same way? Also, wouldn't 2006 production be equally impacted?

shopdog

If the car has a parasitic drain, then it is more likely to go dead quickly if the battery isn't fully charged. The key point is that if the battery isn't being fully charged, then the magnitude of the parasitic drain may be smaller than we've been assuming. In other words, parasitic draws that techs have been shrugging off as too small to cause a problem may in fact be large enough to kill a partially charged battery.

Now since we've been assuming that auto cars don't have this extra parasitic drain, they wouldn't be affected the same way. There isn't good evidence yet that 2006 cars are immune to this problem (though I suspect they are).

Devils Elbow

Your theory on the alternator/charge level makes as much sense as any other - and just for the record, I have had 9 dead battery episodes over Dec. thru Jan. - 2006 A6. I get anywhere from 1 to 10 days in between episodes, not apparently influenced by whether I have the OEM battery in or a new Optima red top. The car is a daily driver, kept in a garage, with a mixture of short hops and longer drives as regular usage. I recharge @ 2amps with a charger after each occurance. PriorityStart keeps me from being stranded.

C5-BRUCE

Do I understand correctly that you've had NINE DBS incidents and own a 2006 A6 car? I've sent you a private message - this doesn't seem to fit the DBS envelope!