You're still in the normal range. I posted on this subject in a thread posted by someone else expressing the same concern and listed about three potential causes, one of which was a possible weak battery. When the owner replaced the battery, voltage came down to a more comfortable level. I believe the specs I posted indicated up to 15.3 volts is within the normal range of what the computer can command (the computer sets voltage output through PWM (pulse width modulation). High electrical loads (lots of stuff going on in the center console) and a weak battery, or connection at the battery.