What is this mystery number in my Satellite Radio display?

[Jeff Cantwell]

Every so often, a number appears on my satellite radio channel display.  The number is usually static (doesn't change).  What in the heck is this?

[Papabear1981]

Your car has a hard drive and if you have a satellite radio channel saved as a favorite, the car will take you to beginning of a song when you change channels

[Les Lex 2018]

Quote the manual: If the radio broadcast is interrupted by another audio output, such as an incoming phone call, the system will automatically cache the interrupted portion and perform time-shift play- back when the interruption ends. Try hitting the pause button during a song and see if that negative number pops up, meaning that you have so many seconds of stored music that you would have missed while pause was on.

XM radio has for many years now, used a caching technique.  That's just my guess. I'll try that tomorrow on my ES 300h.  This function is available when “Auto Pause” is set to on.