Black key got wet wont unlock doors

When you dried it out did you actually take the case apart?

 

When I had my Prius C I washed my key in the washing machine several times. Always worked. Check the battery.

 

The little key is a regular Toyota key. You can make a copy at Home Depot and put it on your keyring. It'll make life a lot easier.

 

Have you taken it apart and cleaned it with something? Do you that then leave it apart to dry really well and put a new battery in it. Best would be if you could remove the curcuit board then clean it with alcohol and dry it really good.

 

The gen2 has an sks button under the steering wheel, is it possible that the button was turned off(inadvertently), and the doors don't unlock because it's off?

 

OP said non-SKS.

I concur with the advice to try a new battery and get the circuit board naked and carefully cleaned and dried. Can't hurt.

Well, except the Gen 2 fob circuit board doesn't get naked so easily. You can slide the back battery cover off the case, but other than that, the case is glued, and has to be cracked apart. But you can buy replacement cases for less than entire fobs.

 

Rice has been tested a LOT and found to be worthless.
Using desiccants to soak up wet electronics - CNET

 

Pure water is only a so-so electrical nuisance, but the rest of the stuff in puddle water is worse. Probably, out of whatever found its way into your fob, the pure water has slowly departed over the past year, leaving the rest. The battery may have been shorted and drained, and the contacts touching the battery may be coated with oxides.

Get it good and clean, contact cleaner on the contacts, under the pushbuttons, residue washed away, fresh battery, see what happens.

A friend once bought a used laptop that had been owned by a heavy smoker. It was pretty much impossible to type on: some keys would never work, othersssssssss wwwwwouuuld reppppeattt liiike maaaaad.

We took the keyboard out and dropped it in a casserole dish with some distilled water, swished it around some, changed the water once or twice as it got gray, then let the keyboard get nice and dry for a few days, and put the laptop back together. Worked fine after that.

It sounds like the passive, RFID chip in your fob still works (what lets you start the car by putting the fob in the slot). As long as that works, you will be able to get another fob and program the car to also recognize its RFID chip and start when it's placed in the slot.

I don't think you'll be able to register a new fob's radio transmitter before resurrecting the one you have. (If you can't bring it back to life, plan B is reseeding the car and registering new fobs from square one, but I'd give your fob a decent try first.)

 

Hopefully it is dry now but by not taking apart the plastic case to dry back then my guess is that some moisture stayed in there and either contaminated or corroded something on the circuit board. Try the steps Skibob suggests in post #6. If that doesn't solve the problem it might be too late to fix. An expensive replacement key might be needed.

BTW, if you happen to crack the plastic case when prying it apart, Amazon sells replacement cases for less than $10. Just make sure you transfer both the circuit board AND the black RFID chip. The two SKS cases I purchased to replace both of my cases also have the bonus of being snap-together pieces so no glue is necessary.