Tune radio as follows: Select a weak radio station (music). Set fader, bass, treble and balance to the center position 0 (RESET or CENTR in display window).
Tune radio to verify reception of AM and FM bands, then in an open area test drive vehicle in a 360° circle to verify reception quality.
If necessary, repeat above test steps with an identical vehicle to perform a comparison test.
Perform the comparison test at the same location and with the same radio stations tuned in.
After replacing one of the components, repeat the above tests again to verify the repair.