First, unless your Pioneer has a really horrible interface, there is almost always a way to enter channel numbers directly. Check you manual. Every receiver/radio I've seen has had some way, albeit not always obvious, to directly tune a channel.
Which channels are you missing?
Do you have a more recent SiriusXM radio (receives all of the channels) or an earlier Sirius OR XM radio (either receives most of the channels - each has their own odd subset, though)?
Are you sure you're subscribed to the channels you're missing?
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