Hi Richard
Depends on the state of the car when you are measuring it. If you have unlocked the car and opened the boot to read it: Yes. As soon as you unlock it the car "wakes-up" and turns on all of the computers which use a lot of Amps. If you are reading it through a window with the car "asleep" then you probably have something which is suffering insomnia and failing to go to sleep when it should 🙂
John