Hint:

Test mode procedure
Terminals of ecuAbbreviations used in manual
...
Using the steering
wheel switches
The steering wheel switches can be used to operate a connected
cellular phone.
Operating a telephone using the steering wheel switches
Volume switch
Increase/decrease the volume
Press and hold:
continuously increase/
decrease the volume
Enter switch
Select an item
...
Road test
Inspect set switch
Push the main switch on.
Drive at a desired speed (40 km/h (25 mph) or
higher).
Inspect "+" switch
Push the main switch button on.
Drive at a desired speed (40 km/h (25 mph) or
higher).
Press the control switch to -/set. ...