Nor can you check the voltage with the car off (as instructed) while driving it. Step by step to test your battery: Park the car. Shut it off. Release the hood. Get out of the car. Let it set several hours or overnight. Open the hood the rest of the way and prop it using the prop provided. Open the cover on the fuse box near the left front wheel well. Open the cover on the positive test/jump point. Get your multimeter and set it to DC volts. Put one probe tip on bare metal. Put the other on the positive test point. Look at the reading on the meter.