I am going with the thought that it is a metering issue.
What meter mode was you in? I would pop it in spot metering and meter right off the car.
Now to anyone that reads this then this is a fun test that will teach you how metering can made a drastic impact. Take a Yellow fruit like a banana or lemon, add a really Red apple, then toss in say a nice and Green apple. Put that camera on spot metering and line those three fruits up next to each other but take three different shots and meter each time off of a different fruit. You will notice that the red is the one that goes way out of whack anytime you meter off of anything but the really red apple. Give it a try. It will open your eyes.