My dealer applied the PI on re-flashing the control module to fix the DBS/phantom battery drain. The car sat at the dealer afterward for three days and started fine. After eight days at my house (I was away on a trip) however, the battery was dead. So I re-installed the Priority Start and called the dealer. They have no new ideas yet. I'll post any subsequent results. BTW it's a '05 MN6 vert, Z-51. Still love the car, of course!

 

Sorry about that. You said the car sat 3 days at dealer, then sat 8 days at house. How much driving did you do between dealer and your house. Its possible its NOW just a low battery.

 

That sounds like normal battery drain that occurs from non-use. If my car, a 2005 Z51 MN6, sits unused for about 12 days, it is also dead. At about that point the Priority Start kicks in. My C4 was the same. These things need juice even when resting.
I run mine very 9 days just to keep the battery charged up, 10 minutes of use or 10 minutes of idling keeps the battery charged. If you have a 2005 your battery is probably dying, particularily if it drained down to zero in the past.

 

Yeah, it may be that the battery is/was weak, but it had already been replaced. In the past, during the 14 months before I started having this problem I had left the car for as long as 2 weeks with no problem. I'll see what develops over the next few weeks.

 

classic DBS is overnight, 2 at most. You just seem to have a bad battery or forgot that radio, onstar, etc take juice to retain memory settings.

 

Actually, all we know is that it was dead after 8 days. It could have died the first day. The key would be to measure the voltage of the battery. If it was something like 3 volts, you know it was DBS! On my one and only full DBS (before I got the priority start), my battery measured 2.1 volts after only a couple of days. If it's just a low battery, it'll probably be 9 or 10 volts.

Mike

 

I have two different drain issues on my 05 Mn6. Real DBS (dead over night), but that's extremely rare. I ALWAYS have "dead after five-six days." I'm hoping the flash fix will cure the latter. Even so, members above who think it's "normal" for a car to go dead after sitting a little over a week..? My Range sits all summer and starts right up when we get back -- two to three months.

 

I shut my radio off before shutting down and nothing since then,,,,

 

My 05 6spd when it does not get a DBS attack (within 3 days) is then safe for at least 3 weeks. (I have done this a couple times last year) I can see the blinking light by the radio as I walk by, if no blink no start.

Since I have had 3 attacks, if I am not planning to use car I NOW hook up a tender and for the long winter (comming soon DAM) I will tender as I did last year.

 

An excellent observation/suggestion.

The irony of the thing being fixed only to have one of GM's notoriously bad batteries installed just to confuse matters is more than ironic, it'd be infuriating.

First thing I'd do is have that "new" battery load tested.

 

I have left my 05 Z51 sit for a month and it started right up. I have had two instances of DBS, one this summer and one last summer. I am religious in my shutdown sequence so I know it wasn't that.

Its possible it was a low battery.

 

Warning...........long post or rant........don't flame me or expect me to be the battery guru as I am not, but I do work with high current batteries, both SLA, open LA, NiCad, Li-Ion, etc. every day!

If your battery reads 3 volts or less......time for a new battery. Your dealer should know this! Most times you run a SLA battery down past 40% capacity there is non reverseable damage to the chemicals. With a open lead acid battery you can change the electrolyte and get it working again.

Now a lot of ppl are going to flame me saying they have had their batteries down to 0 volts and simply jump started the car and the alternator recharge the battery and it last 8 more years.....blah, blah, blah. Yeah maybe, but everytime your battery dies and you try to start your car with it, the overall life of the battery is cut by something like 1/3. A new battery is cheap insurance. Also if your battery is not holding up for some time like 10 days or more, then you have some serious current draw when the car is shut off. If your battery has like 400 amp hour capacity then it should last something like 240 hours at 1 amp draw at 12 volts and then the voltage will start dropping with the current. Just simple Ohms law. My '93 Mazada sets for 2-3 weeks at a time and then starts with no problems, my '03 Lex sets for at least 1 week and does not have any problems. My Vette is my daily driver and Vettes take a lot of current to start.

The bottom line is you may or may not have the DBS. Mine went dead about 1 month ago and I jump started it. The dealer tested it as hard as possible and put the slow current, professional charger on it overnight, as the alternator can NOT recharge a dead battery........period! They tested it again with the computer controlled charging ckt tester/battery tester. No problems noted, no codes set. I have been monitoring the voltage and the battery looks ok, but the dealer knows that this has happened and the battery life is now shorter than a battery that has never been dead. Sorry if I broke anybodies bubble!

 

Also, you might simply have your dealer check to see if something else is causing the drain. You know, mulit-meter, pulling fuses until it stops the drain?

 

Thanks for sharing!

 

No argument, although as you point out, it is possible to run one for a long time once it has been deep discharged. For me, I replaced mine with a deep discharge battery on my first DBS and also installed a Priority Start so at least I won't go broke replacing batteries. Worked fine and in 2 years, I've had the one true episode of DBS, one that was stopped successfully by the Priority Start and another that I caught mid DBS a few minutes after I parked it before it ever tripped the Priority Start. The last two were on the Deka Intimidator deep discharge battery (similar to Optima but cheaper).

Mike

 

I would think that if you caught a discharge real soon there would be little or no damage done. I suspect that the damage occurs when the battery sits dead.

 

I don't believe that is normal drain. I have left my 06-Z51 for 3 weeks several times and it started fine with the original battery. Any of my other GM vehicles will do the same.

 

If it were my Corvette I would buy a new battery to eliminate that possibility of being the problem.

 

My 05 MN6 had been sitting for about a week. My daughter gets in the passenger side and the door opened fine etc. I forgot something and had to run back in the house and upon my return I attempted to open the driver's door to no avail. Dead battery. There was enough power for my daughter to get in and not enough for me. I opened the driver's door using the trunk release, pushed in the cigarette lighter and the Priority Start closed the circuit so I could start the car. I have had to use the Priority Start at least 3 times since installing it. I have given up on the dealership or Chevrolet. I did discuss the issue with Customer Service in Florida and they asked me what my intentions were with regard to the Lemon Law. This question was in response to my letter documenting the problem as required by CA law. However, I don't know if I want to go that route. This is very frustrating!!!

 

Interesting!
Probably NOT DBS!
After more than 2 days of DBS with a NEW battery, you'd be stone cold dead in the water. No door would open because volts is zero or next to it. If she opened the door at day #7 it probably wasn't DBS, and more likely a failing battery for any other reason.