NOTE: as pointed out in the comments, none of these quick verification steps actually guarantees that the airplane you clambered into is certified for LPV approaches, or for IFR GPS usage at all!
On boot, a 430W will display that it's a 430W:
Aside from that, I'm sure there's a version info screen somewhere (on both G1000 and GNS430), but the best solution ...
The FAA website predicts pre-flight whether RAIM will be available
The RAIM algorithm will tell you during your flight if GPS is working correctly.
The pre-flight FAA website check is not a substitute for the use of the RAIM function during flight. It will only show whether the RAIM function is available during flight.
RAIM stands for Receiver ...
For the 430: use the outer knob to scroll to the AUX group. On page 4 (setup 2) there should be an item called SBAS SELECTION. If there is, it is WAAS equipped, however, verify WAAS is ON.
Similarly, if on the NAV group you scroll to the satellites page they will display as green rather than blue. But like before, verify WAAS is ON in the 'Setup 2' page of ...
If you take a look at the manual for the 430 you will see that you can only load one approach at a time.
Turn the large right knob to highlight ‘Load?’ or ‘Activate?’
(approaches only) and press the ENT Key. (‘Load?’ adds the procedure
to the flight plan without immediately using it for navigation
guidance. This allows the pilot to continue navigating the ...
Yes, both allow you to “LOAD” an approach without “ACTIVATE”-ing it. Slow down for just a moment when plugging in the approach. Or, better yet, practice doing it in a AADT or higher sim or on the ground until it is muscle memory.
Try finding Max Trescott’s G1000 book.
Here are some thoughts.
Do you still have a previous approach loaded / activated? Can you delete the old approach before loading the new one?
Are you in the middle of a missed approach? Try unsuspending.
If neither of these work, see if you can provide specific examples of approaches that do and don't work properly.
Answer lies on AIM 5-1-16 "rnav and RNP operations" paragraph f:
f. During the pre−flight planning phase RAIM prediction must be
performed if TSO−C129() equipment is used to solely satisfy the RNAV
and RNP requirement [...] Operators may satisfy the predictive RAIM
requirement through any one of the following methods: [...] 2.
Operators may use ...