I have a 2004 XJ8 with the GPS console. I pushed all the buttons and fiddled with all the knobs, but I can't find the stereo equalizer, or even a treble and base adjustment. Is there no way to adjust treble and bass?

The stereo controls are not explained in the car's user manual.

 

Push a "Mode" button,next to the volume knob.

 

There's a separate manual for the touchscreen. Next to the turning knob for volume is a button, MODE, this brings up the menu with those options. Not sure if the display has to be on audio or not.

Guus