Originally Posted by rockinrog
So the 911 will tell you if your battery is on its last leg?
Not exactly, but it shows the engine computer's idea of the battery voltage, which turns out to be higher than the value my GPS is showing. Since my GPS shows a lower value, I thought that my battery was putting out only about 11.7 volts with the ignition off. It turns out that the system is at about 12.5 volts instead, which is quite healthy.