The Nav voice volume is not set by the volume control in the menu (under setting (or set)), the one with the bar and the voice saying "louder/quieter" ) in the system setup, so setting it to anything here is a complete waste of time... (unless you want to mute the radio when being given a voice command).

This is for setting the amount of attenuation of the radio in relation to the value of the navigation voice.

You can set the loudness of the navigation unit in two places.

1: via the TP option on the radio, get to the TP volume button and set the volume up or down as required, this will set the TP volume (traffic news etc) AND the Sat Nav voice volume (this is in the Navigation manual, that came with the car.)

Note:: TP Volume: Traffic Patrol
Provides adjustment for traffic report minimum value. On some vehicles this setting can affect the NAV volume. (on mine it does)
Refer to Service Bulletin B84 02 03.

OR

2: Via the secret menu, and setting the GAL value.

Use the Radio service menu (the link is to a pdf file).
http://tinyurl.com/3c4poa

Note:: GAL: Speed sensitive volume control.
The speed sensitive volume control can be adjusted from level 1-6 using the 6 preset audio buttons. Radio volume increases more at level 6 and less at level 1 (road speed dependent).

Strictly speaking you should not use this to adjust the Nav voice, as it's for adjusting the radio's speed sensitive volume control only, but as a side effect it adjusts the Nav voice as well.

I used the TP option and it has now fixed the Nav voice volume. (mine was too loud).

Confusing I know, and not logical, but that's the oddities of software engineers.

Hope this helps

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Sept 03, M3, Silver Grey. Retro-fits: Modded Mk4 DVD Drive, OEM Bluetooth, VR Control, Rainbow Speaker Upgrade, Sony SOT Amp, HK Sub, CCFL, Intravee II, NightMode.