I had a few slow starts over the past week where I push button & it seemed like it wasn't going to start but it did. Then I go to start, push button, it does the slow sound and this time goes dead.
~Battery less than year old & reading 14.7 when measured.
~When I 1st put the negative jumper cable on the terminal, the car "lit up", the kind where the battery has been dead & the radio comes blairing on, beeping noises, accessory light comes on (start button).
~Push start button, it dies again.
~Attempt to get a jump from another car, nothing. There's a measurement box on the jumper cables & it's reading 14.7 for my battery.
History
~Alternator replaced 2 years ago when experiencing frequent "dead battery" and always remedied by jumping. Autozone able to determine alternator was bad. No problems since replaced alternator until now. Also replaced battery after replacing alternator because it was drained too much from the frequent jumps. (Had to replace that battery under warranty a year ago).

~After researching a little, I checked relay #55, it's good.
~Battery terminals clean and connected tight.
~Key fob has brand new battery AND I put fob in the glove box slot when attempting to start.

Anyone else experienced this? It doesn't seem like battery to me since it's reading 14.7 and not able to start with a jump. I always try to work on problems myself to save $$ of course. C6 2010 Manual

 

Was battery 'load tested'?
Could be bad cell(s) showing 14.7, yet not amps.
Reported happening many times.

Don't assume, get it load tested.

 

Because the battery VOLTAGE is reading 14.7 doesn't mean the battery is good...get it load tested...it can read 14.7 for a split second until those amps start flowing...then nothing !!...sometimes with a dead battery the car may not start even with a jump...I've seen it...if you know how to voltage drop the starting system with your DMM I would do that.

 

I didn't even know what "load testing" was. This battery was repaced on warranty almost a year ago because of the battery being bad after a year. It just might be the brand of battery.
Thank you!

 

Replace bettery, acquire a reputable brand this time.
DON'T be surprised if she fires right-up.

 

My son got me the battery when I had to replace the alternator; he's only 25 & I know he bought the least expensive battery, lol. I hope you are correct! Definitely going to buy a better one. If you have a suggestion please let me know. I'll be going to get a new one in about an hour, otherwise I'm gonna research for best recommendations. I'll let you know if it works! Thank you!

 

RC (Reserve Capacity) is more important than CCA...get a battery with the highest RC (minutes) that you can get...CCA not that important...more CCA doesn't mean the car will start any better...it only draws about 600-650 amps for a split second to get the motor turning (inrush current) and once the engine is cranking the starter is only drawing around 150 amps !!

 

K, installed good battery (Optima Yellow AGM Group 35, Reserve Capacity 120 minutes). It lit up the dash, however when I push start button it dies. But if I wiggle the negative terminal cord, it lights up dash again. I did the "load capacity" & it was 12.4.

I think either the terminal connector isn't tight enough, even though it looks like it is; or there's a problem with the cable?

 

That is why we voltage drop the starting system to see exactly where your problem lies...I'd get rid of those crappy OE terminals and get something much better....if you are able to turn the battery terminals by hand they are not tight.

 

If it won't start after you confirm the cables are connected tightly to the new battery, check the terminal nut on the starter solenoid. Remove the negative battery cable first, then jack up the car and make sure the nut is tight on the solenoid. If the stud itself is loose you'll need a new solenoid.

 

I thought I uploaded this, but I don't see it. The terminal that's tightened with the bolt doesn't move, it's when I push on the cord that the dash lights up. (I should have been more specific). It does look like there's rust on the silver clamp.

 

Omygoodness, I GOT IT! THANKS TO ALL OF YOUR INPUT! It turns out the terminal was not pushed down all the way; wasn't as far down as it needed to be! The pic shows now there's a "silver bump" where before the silver bump was flat. To the one who suggested the new battery, even though it wasn't the battery having enough load, I'm still SO GLAD I have the right battery to handle this car. But thank you all! This ended up being a simple fix. (I feel ridiculous too, lol)