Washington - XM Satellite Radio will provide refunds to consumers for its 24-hour service outage earlier this week.

XM said subscribers who request a refund by calling a toll-free number will receive a credit for two days of service on a future bill.

The service outage was due to a software glitch, which occurred when loading software to one of XM’s four satellites called XM-3. This satellite is responsible for communicating with XM’s repeater network. The repeaters are used in urban markets where buildings may block the satellites.

Separately, XM announced that it launched a trial satellite radio program for GM-certified used vehicles including Cadillac and Hummer certified pre-owned models. XM will be available in more than 115,000 of these vehicles in 2007, expanding to more than 168,000 in 2008. XM already has a certified pre-owned program through Honda and Acura, which was launched last year.