One way is by:
1: Be sure ignition switch is off for at least 15 Seconds
2: Turn ignition switch to “Accessories”
3: When stereo’s “Warning Screen” displays, press & hold the stereo’s “Power/Mute” button until “Service Menu” is displayed (approximately 15 seconds)
DTC Codes are displayed in there, I just don't remember if they're right there on that menu or in another selection group.
This "Service Menu" is how I get in to reset my service milage (on the info screens) after doing an oil changes (it's under "Reset" then "Milage Reset"). There might be an easier way, but I know it can be accessed this way too.
As far as the 2 codes above, I have gotten those codes before, when the tour pack was off and I had not set my fader all the way forward. Never got a CEL though. On mine the codes would clear themselves if/when I hooked the tour pack back up or moved the fader all the way to the front speakers.