Depending on the length of time the power was interrupted, your system may require GPS initialization.

If initialization is not necessary, the system proceeds directly to the Startup Confirmation screen.
If the system fails to locate a sufficient number of satellites to locate your position within 10 minutes, the following screen is displayed.

If you are experiencing GPS reception problems:
Output Shaft (Countershaft) Speed Sensor Replacement (A/T)
Remove the air cleaner assembly.
Disconnect the output shaft (countershaft) speed sensor connector, and
remove the output shaft (countershaft) speed sensor (A).
...
Driver's Airbag Replacement
NOTE:
If replacing the driver's airbag after deployment, refer to
Component Replacement/Inspection After Deployment for a
complete list of other parts that must also be replaced.
...
Warm Up TWC Removal/Installation
NOTE: If the warm up TWC is damaged internally, inspect the under-floor TWC
for debris.
Raise the vehicle on a lift.
Remove the bolts (A).
Lower the vehicle.
...