Well, according to this summary of Voyager's telecommunications systems by JPL's Deep Space Communications and Navigation Systems Center of Excellence (DESCANSO), the uplink frequency (Earth to Voyager) is 2113.3 MHz. Here's the downlink (Voyager to Earth) frequencies of both Voyager 1 and 2:
So Voyager 2 uses a frequency of 2295 MHz (S-band) or 8415 MHz (X-band).