Bought an '07, loaded, this last August. Have had no problems until recently...In the last two weeks, the battery has died unexpectedly twice. On the second occasion, tonight, the car was running at idle when it suddenly died unexpectedly. Upon trying to restart, no go, yet all the lights work, dash lights, etc. My suspicion is a bad cell. A jump gets the car going and no codes are set.

Given all this, is there any ideas anybody has? And yes, am going to take it to the dealer on Monday.

Sounds like a bad battery to me, now I am not sure if the 03 and 07 have the same charging system, but mine was doing the same damn thing, put a new battery in it and viola sucess!

1. GM cars have AC Delco batteries.
2. Several years ago, those batteries were known for not regaining full strength after a partial/total discharge.
3. I believe GM resolved those problems, but...
4. New cars sit on dealer lots for many many months. If dealer does not start cars regularly, the battery will lose charge. Parasitic effect (on all brands of cars).
5. If battery totally fails, GM will not replace battery for dealer since dealer needs to show proof that he/she has plan to maintain new car batteries. As a result, dealer can send you home with a weak battery. If you come back the next day, GM will pay for a new batt. Prior to sale, GM will not replace batt.
6. In my opinion, you likely had a weak batt. Dealer will now replace it at no charge to you.

I use a trickle charge on my Caddies and my Trans Am once or twice per week. Charging batt while running car and driving is not good for new alternators. It frankly can burn them up. Parasitic effect is what causes batts to lose charge.

All manufact have this problem.

I'll take her in tomorrow and see what the dealer says. Wish me luck.

Just go buy you a new yellow top optima battery if it is that

Just go buy you a new yellow top optima battery if it is that
That is my plan if they won't replace the battery. Do you have the Optima model # perchance?

So? What did you find out?

That is my plan if they won't replace the battery. Do you have the Optima model # perchance?


I just went to Sams and bought the yellow top they had there. It will work with GM models and imports too. I think it was around $120

The Optima site shows no battery for the CTS - due to the posts on top. What model yellow-top did you get to fit in the CTS?

The Optima site shows no battery for the CTS - due to the posts on top. What model yellow-top did you get to fit in the CTS?

At Sams or your local retailer they have the post AND the GM front mounted posts...the optima yellow comes like this its a little more expensive but it will fit any car...I just bought it and installed it...simple as that. Yes Optima's website doesn't show a model to be used with the CTS but again it didn't show it for my TC, Accord, or my Acura TL. Their website is out of date. Just get one with the dual posts for all makes and you'll be fine

So? What did you find out?
Dealer still has the car. "Needed more time" which probably means they hadn't gotten to it yet. :bigroll: Interestingly enough the battery died AGAIN when I went to take it to the dealer so I have high hopes. The service writer agreed that it sounded like a cell going bad but he was more interested in the fact that it had died once while it was running at idle and then wouldn't start so they may be doing some in depth diagnostics on the whole charging system.

1. GM cars have AC Delco batteries.
2. Several years ago, those batteries were known for not regaining full strength after a partial/total discharge.
3. I believe GM resolved those problems, but...
4. New cars sit on dealer lots for many many months. If dealer does not start cars regularly, the battery will lose charge. Parasitic effect (on all brands of cars).
5. If battery totally fails, GM will not replace battery for dealer since dealer needs to show proof that he/she has plan to maintain new car batteries. As a result, dealer can send you home with a weak battery. If you come back the next day, GM will pay for a new batt. Prior to sale, GM will not replace batt.
6. In my opinion, you likely had a weak batt. Dealer will now replace it at no charge to you.

I use a trickle charge on my Caddies and my Trans Am once or twice per week. Charging batt while running car and driving is not good for new alternators. It frankly can burn them up. Parasitic effect is what causes batts to lose charge.

All manufact have this problem.
Alternators are on the car to charge the battery as well as to supply current for all the accessories. In fact, on todays cars battery charging is a minor load compared to everything else. Recharging a totally dead battery has absolutely no detectable effect on an alternator. Recharging a totally dead battery requires about 30 amps of current. The alternator can supply 180amps+. The alternator regulator is fully temperature compensated and keeps everything nicely under control. The automobile electrical system is, in fact, the very best way to recharge a battery. Bigbird has laid an egg here.

Dealership just called and the car is ready. Battery checked out bad and they replaced it.
So even the 07's are having battery issues. This has been an ongoing issue with GM for about 3 years now. So be forewarned, if you have the original OEM battery, it may go bad on you. I attribute mine to sitting on the lot for over a year and no maintenance or care for the battery.

Modern automobiles will discharge the battery over time because of all of the electronics that must be "kept alive" so memory will not be lost. When a lead acid battery sits partially discharged, the plates become sulphated and this is an irreversable condition. The battery will prematurely fail in an automobile that regularly sits for extended periods. A battery in a car sitting on a car lot day after day will go to hell unless a trickle charger is applied. Drive the car regularly.

Modern automobiles will discharge the battery over time because of all of the electronics that must be "kept alive" so memory will not be lost. When a lead acid battery sits partially discharged, the plates become sulphated and this is an irreversable condition. The battery will prematurely fail in an automobile that regularly sits for extended periods. A battery in a car sitting on a car lot day after day will go to hell unless a trickle charger is applied. Drive the car regularly.

What he said :yeah: Only he said it better. Lets hope the new battery lasts longer than 3 months. ;)

PS battery was dead when they went to start it this AM, I'm pretty sure that helped my case.

I contacted the Optima people. They said that some of their batteries have side posts, but ALL of their batteries have top posts. They said that with top posts, their batteries will not fit in the CTS and still clear the hood. That's why they don't list the CTS.

Well glad to here is was the battery.