Panel under car came loose...

I believe it's only purpose is to smooth out the air flow on the underside for better MPG.
The dealer should be able to do a quick fix for you.
Have a good trip.

Dan

 

The dealership could be part of the problem, too. If it's similar to the hatchback, the (rushed) mechanics are likely just opening the local flap, which can stress the hinge, and/or rushing removal/install of the cover, losing/breaking fasteners. To be fair, it could also be due to driving over a few curbs or sim.

 

Unfortunately, as Mendel mentioned, the dealers don't follow the prescribed repair manual instructions, which says to remove the entire engine under cover when changing the oil. They typically just open the flap beneath the oil filter, which has a weak plastic hinge. Mine fell off on the highway and I replaced the entire panel. I do my own oil changes now, and remove the entire cover, which gives me the opportunity to look around underneath for any other potential problems. Good luck.

 

I have had mechanics break the fasteners. It would be best to rig it up at the house before going to the dealership rather than further damaging the cover.

 

climb under with some bailing wire and snips. you can do a quick fix for your trip and something more complete when time is available.

 

Every time that I inspected the undercover, after a FREE oil change performed by my dealer, at least one or two of those plastic "push in" rivet clips were loose or improperly fastened. That was with the first three oil changes.

If you have eve removed the entire under engine panel, you'd find that the "leading front edge" is held on with a number of M6 bolts threaded into captive welded in nuts for this high stress point. By using plastic rivets, Toyota engineers failed to realize the stress that the "trailing edge" back at the oil change door gets.

After the third oil change, I took action and installed two M6 "RivNuts" into the two larger holes that took the gray headed plastic rivets. No drilling on the metal underneath was needed, since the holes were the correct diameter.

I have the special installing tool, but for two "RivNuts," a simple tool can be easily made.

Make Your Own RivNut Tool | Carolina Rover Owners Club

One "RivNut" is all that's needed on the panel and one on the oil change door.

For the fourth FREE oil change, the dealer, again failed to replace the plastic rivets correctly, but the bolts held fast.