My 2008 C6 automatic has begun to have starting problems. My son drove it last night and said that it was hard to start and on the way home the dashboard lit up (ABS warning, Service Charging System). I cranked and drove it this morning and everything seemed fine. However the voltage was barely reading 13 V. on the dash. I bought the car from a Chevrolet dealer about 3 months ago and have no idea how old the battery (Delco) is, so I bought a new 650 CCA battery and put in it.

The strange thing is after I replaced the battery it began to have starting problems as my son described. It would give one click, as if it had a weak battery or a bad solenoid, but after a few tries it would fire right up. Then it would refuse to start, either one click or a slow crank before it fired up. Sometimes it starts and sometimes it won't, this with a new fully charged battery.

Even when it won't start the dash lights, radio, and power windows work. But the strange thing is that with the new battery the voltage shown on the dash gauge is LESS than it was with the old battery. I checked the tightness of the connections between the battery cable and the battery terminals and I had cleaned the corrosion from the cable terminals before installing the new battery. When the engine is revved the voltmeter on the dash doesn't budge. I haven't gone under the car to check the connection to the starter or the solenoid.

I don't want to take it to the dealer if it is a simple problem I can fix and here it is right at Christmas so it would probably be next week before the dealer could get to it. Any ideas?

 

is based upon alternator output and has nothing to do with the battery other than showing the value of the power being sent to the battery- you are low on the Volt side so I suspect an alternator issue.
I also suspect an issue with the battery cable and or the connections at the starter.
I would replace the + & - cables and make sure all connections are tight.
I would pull the Alternator and take it in for bench testing and proceed as recommended.
While you are at it replace the battery in your FOB's.

 

I replaced the FOB batteries right after I bought the car.

I always thought a Voltmeter measured the battery charge and an Ammeter measured alternator output.

I'll check connections to the starter, solenoid, and alternator tomorrow.

 

No. Voltage shown in gauge is volts being sent to battery. Maybe I missed it but did you check the cables completely or better yet, replace when you replaced the battery?

 

Don't forget to check the other end of the ground cable.

 

I had the Same issue with my 2008 and I switched batteries, starter, and alternators. Each part offered a short term fix but it would come back. I even tried running an extra ground wire ( 10g ) to the back of the block. What fixed the issue was buying a new set of battery cables, I replaced it all and the car runs fine now.

For now check the cable connection on your STARTER!!! That nut would work its self lose.

 

This sounds like starter solenoid to me. I had these exact same symptoms two different times. Both times it was the starter. Get it fixed now because it will only get more and more frequent and then one day it just won't start at all. Ask me how I know.

It happened to me twice because I have long tube headers that weren't heat wrapped. The heat closer than stock headers toasted both the starters over a period of about 60,000 miles but once I got the passenger side header wrapped my starter has been fine ever since. May be different from your situation but something to keep in mind just in case so you don't make the same mistakes I did

 

You were right. It was the starter and it did finally refuse to start at all. This happened after the dealer misdiagnosed the problem as the alternator, which they replaced. After I returned with the same problem they said it was the positive battery cable. Rather than continue to let them chase the problem (and empty my wallet) by replacing parts instead of properly diagnosing it, I took (had the car towed) to an independent shop I trust. They diagnosed it as the starter, replaced it, and (knock on wood) I haven't had any charging or starting problem the past three days. I did have them replace the battery cables anyway with a set I ordered from Amazon because there was green corrosion on the negative cable and the positive cable to the solenoid located just inches from the catalytic converter (totally stock exhaust system) was burned.

So now I have a new battery, rebuilt alternator, new battery cables, and rebuilt starter. At least I shouldn't have to worry about any of those for a while, but I am P.O.'d with the dealership service department for being unable to properly diagnose the problem to begin with. That's why I took it them, figuring they would have the best diagnostic equipment around and technicians who were familiar with Corvettes (they sell quite a few for such a small dealership).