when you got no navi voice or sound on your clarion or your original sd card is defect !!
try this link below.
then you can use Here of igo/Tomtom maps.
my clarion nx403ev is working again :023:
change in the sys.txt your device clarion unit name.
that's all.
example type="CLARION_NX501E"
put IN CONTENT your country voice/lang/map on sd card.
don't forget make a copy first of ...