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Car locking itself... repeatedly... killing battery

3K views 25 replies 9 participants last post by  CadiTamer 
#1 · (Edited)
Hi guys!

I'm having all sorts of dumb issues lately.

About a week ago, i went remote started my car, and it failed to start due to a low battery. Jumped it off, drove for about an hour, all was well. Car had been sitting for about 30 hours at that point.

A few days later, after the car had sat for a while again, the battery was dead again. Completely dead this time, though. Went ahead and jumped it off, drove, and all has been well since, though my friend has noticed something strange.

The car seems to be repeatedly locking itself. I have the auto lock feature turned on, so it should lock when i walk away from it, but it seems to be constantly locking itself throughout the day/night. I'm thinking this is an issue with the RCDLR, though i could be wrong. Does anyone know what could be causing this?

I've also noticed that on days that are more humid, the trunk likes to open itself randomly. Sometimes it'll do it once or twice a day while the car is running, and other times it might do it 20 or 30 times in an hour while the car is off. So far my solution to this has been to flip the valet switch, but it seems that it still happens every now and then...

Thanks!
 
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#2 · (Edited)
I'd start by replacing what appears to be a weak battery. These things can do some weird things with low voltage present.

And if you take this route get a group 78 battery vs. the recommended group 101...You'll get more CCA's, it fits just fine, and it's MUCH cheaper.
 
#3 ·
I would think that with all the posts about battery trouble on this forum that the first thing that an owner would buy is a battery load tester. I got mine at NAPA. They are way cheaper than any tow or battery call out service you will find anywhere and along with a jump box will make you self-sufficient. I suppose nowdays the average bear would rather sit and squall and wait for somebody to rescue them.
 
#4 ·
The battery in it was purchased when i bought the car in December, though i will admit that it looks to be the wrong size. (It's pretty small compared to what it looks like can fit)

Would a weak battery cause the car to remain active when it's off? I've read that low voltage can cause the issues with the trunk, though i'm pretty sure the little button on the driver's door is the issue. (It doesn't work, is basically my guessing there.)

I did have the battery tested at AutoZone, and they said it was fine, though i don't know how much faith I have in their tool.

I do have a jump box in the trunk, as i knew i'd likely need it one day :)
 
#5 ·
IMHO, a free test is worth what it cost. $0. If the battery has been drained twice to the point where it needed a jump and once 'completely' it's likely been damaged anyway. Auto batteries are not designed to ever be discharged that far.

Koz has once again scored a direct hit. Even now that I know I have a good battery and no trouble, I still carry a jump-pack and charge it regularly. I'm occasionally asked to provide a jump and I like to help my friends. But I don't want to risk my car's electronics. Besides, you just never know, I might need a boost myself.
 
#6 ·
I know one day my friend moved the car and didn't get it all the way in park. Apparently that causes the car to stay in accessory mode, and he didn't notice. (How he missed the stereo being on is beyond me...)
When I got to the car later that day, the battery was showing five volts. While that was a while ago (2 or 3 months) I remember wondering if the battery was a goner back then. Charged it overnight on a charger, and it seemed happy. Maybe that's finally catching up to me.

I'll go ahead and drop a new battery (of the proper size) in this week. Hopefully that'll solve the issues.


Thanks guys!
 
#7 ·
It's your car; do as you like. I just don't think it makes good sense to pay a premium price for a Type 101 battery which the Battery Council International rates at 540 CCA when a Type 78 with 800 CCA will fit and costs less. These cars place heavy demands on a battery and greater reserves serve to stabilize the electrical system.

GM upgraded the STS to a Type 48 battery in 2008, which was rated at 730 CCA for its first two years and then the BCI downgraded the Delco 48 to the 660 CCA rating it maintains today in the XTS.

BCI Battery Replacement Data Book

----------

PS: My wife & I have been using Optima RedTop 8078-109 for a few years with zero difficulty. AFAIK, both had been original prior to 2011.
 
#9 ·
My '06 came with a 101 battery that was dead on the showroom floor for who knows how long. I bought the car as new in '07 so it must have been months. The battery never gave me a moments trouble but when it got to be six years old I replaced it with another 101 because I didn't want to go into the winter with something questionable. I still have the original battery and it still holds a charge. My car has never failed to start and has never stranded me even in -50F weather. My experience tells me that the OEM battery is completely adequate as supplied.
 
#10 ·
I'm sure the 101 is perfectly adequate but I'm not one to pay more for less...The price of the 101 is outrageous compared to the 78 and the 78 gives you more CCA's, that was a no brainer to me.
 
#13 ·
I would trust an AC Delco to work properly even after a complete discharge... I'm pretty convinced the battery in this car is the cheapest that could be bought (judging by the lack of labeling, and the typical appearance of things on the car, as well as things i've found since i've owned it), so i'm sure a few good discharges to 5 volts would probably ruin it. It also drops from the normal 13 volts to below 12 within a few hours of shutdown, and i'm not seeing anything pulling power from the battery, so i'm betting a dead cell at this point, and the car is just overcharging the remaining cells, not knowing what's wrong.

I've had cars with dead cells before that weren't so intelligent, and they would just charge it to 12 volts, and it'd be dead the next morning... With the STS having the IPM controlling and monitoring the charging of the battery, it wouldn't surprise me at all if it's charging it until it hits the correct voltage, or if it's continually charging it while the car is running due to the increased current draw of the dead cell in the battery.

Anywho, as soon as i'm not completely broke (between jobs currently; new one starts Monday) a new battery will be showing up in my STS :)
 
#22 ·
Key fob, no. But, it looks like this may have been caused by a soda...

Noticed the trunk was popping itself nearly non-stop at my friend's house today. Got to looking around when i got home. Pulled the battery out of the keyfob, and it was still happening. Pulled the trunk switch out of the door, and unplugged it, and it stopped.

Huh. That's weird. Took the switch in, and was getting continuity between pins 1 and 3 (the pins for the button). Pulled the button apart (very easy to do, just plastic clips), and found that half the switch was completely covered in corrosion. Cleaned it off with some alcohol, put it back together, plugged it back in, and no popping trunk.

I assume what was happening is the trunk was popping, and then the car would later lock itself. Since the high beams come on when the trunk pops, i bet if that happened enough it would kill the battery pretty quickly. We'll see what happens, now.

I'm sure i still need a battery, as this one is not holding voltage like it should. Put the charger on it on a 25 amp setting, and it went up to 30 amps and parked there for about 30 minutes, and then fell to about 2 amps over the next two hours, and stayed there. I'll see if i have any more issues with popping trunks, and then i'll work from there.

I'm gonna feel really dumb if the entire issue was a little corrosion on a switch.
 
#16 ·
A couple of years ago my car had the exact same symptom. I could hear the doors unlocking every 10 seconds or so after turning it off. My AC Delco was 1 yr. old so I didn't suspect the battery. I had it tested and was told it was OK but it was slow to take a charge. They replaced it for free but I swapped it out for an Interstate I had laying around before they got the new one in and my problem with the locks disappeared.

Recently, the Interstate started acting weird. I had to pull my door handle multiple times before the door would open. I thought the micro switch was failing. Then after a couple of days I went to close my windows after turning off the engine and they all cranked real slow. Yikes, my battery must be low on a charge so I hooked up the charger and it went up to 15 amps on the 10 amp setting. It charged like that for 30 minutes before eventually coming down to 5 amps, but it wouldn't go any lower. Tried to start the engine and it was very slow cranking. Pulled the Interstate out and put in the new 2 yr. old AC Delco and once again, all's well in the 'hood... I mean under the hood!

I was using the AC Delco for my hobby to recharge my Li-Po's and I want to return it to that duty. So I'm thinking of getting a 78 Duracell from Sam's for $96. They have 850CCA, 3 yr. full replacement and 8 yr prorated.

This car has been death on batteries and I want to be ready for this winter.

Does anyone know if the original 101 battery cover fits over the 78? Or do I have to go "commando" style!!
 
#21 ·
After a little research I found the difference between the 78 and the 101 but for the life of me I cannot figure out why the 101 is significantly more expensive with a lower max CCA. Overall size the 78 is 5/8" taller. The other dimensions are identical so the 78 is slightly larger but can offer up to 300 more CCA than the 101! I just don't get it.

Does the 101 offer something else? Was it specially made to fit the Sigma platform? Is it called for in any other platform?

I'm puzzled.
 
#24 ·
...In fact, I owned the car for over a year before learning about that button. I hope that solves your problem for good.
I'm one of those that try to really grind the manual down to a fine powder when it comes to features. I miss quite a few anyway but I learn a lot of things which are especially helpful in feature loaded cars like these. I think I had mine for 2 years before I read about the valet switch, then it took a couple of months before I actually found it.

Not that I ever have a need for it, but just to know that it's there! Or, how the air quality sensor works the A/C (actually, that took a little experimentation!) I'm not sure if all STS's have those but it was still a surprise!
 
#26 ·
Well, with the key fob and the button on the actual trunk, i don't even know why that dumb button is there.

Seems the issue is resolved. Haven't had anything happen lately, and every time i've gone to the car the trunk has been shut.

"I woke up this morning, got in the car, and the trunk was still shut. It's the little things in life."
 
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