See also:

MT models
The key can be turned from “Acc” to “LOCK” only when the key is pushed in while turning it. ...

Acc
In this position the electrical accessories (audio, accessory power outlet, etc.) can be used. ...

When CD is in the player (type A)/ When playing back all CDs in the player (type B)
When the “CD/AUX” button is pressed, the player will start playback. ...