Key Not Detected After Maintenance

2010 Prius get the coolant light on .5 miles from relatives house. Pull over for a minute to assess. Coolant level was appropriate.

Engine light and hybrid system light comes on, I read the code and it’s for water pump control unit.

Drive carefully slow without hearing engine come on over to relatives home garage. Following morning Disconnect battery, replaced water pump(old water pump was pretty stiff and locked up). Button everything back up.

Reconnected the battery and the car will not detect the key at all. Placed it near the start switch with my foot on the brakes and still nothing.

Swapped out fob battery for a new battery. The little red light still works and flashes. 12v auxiliary battery is fairly new I replaced it 2 years ago, haven’t done a health check but headlights come on, door locks work all that.

Doors lock and unlock with physical key but they do not lock and unlock with the fob even with a new battery. So strange. The flashing triangle with exclamation and lock and car light are on. It says touch key against start button and depress brake pedal.

I have no idea what is interfering with the immobilizer setting. There is a Tesla charger in this garage with a big wire stretched across the cieling and down the other side. but we turned it off and wrapped the wire up after becoming suspicious of interference, no difference.

I tried opening and closing all the doors to make sure one wasn’t left open but I was reading that somehow the rear hatch might cause this. The rear hatch seems to be functioning properly.

I have another key one hour away I’m worried I will drive back here and the car still won’t work and I’ll have wasted 3 hours after going back home again. What could be happening here?

 

I also did an oil change while I was down there.

 

I don’t have multimeter so I brought the battery to advanced auto. Tested the battery it says the battery was good but it needs to be charged.
The voltage was at 12.6.

The battery is currently charging at the store. Will update.

 

Fuse Box Diagram Toyota Prius (XW30; 2010-2015)

I found both SKS fuses. One in the passenger compartment. 10amp fuse #37 was not blown.

I found the fuse under the hood for the smart key #10 7.5 amp fuse which was also not blown.

 

Battery got fully charged and positive health check. New voltage of battery installed in the car is 12.81V from positive to negative. 12.81v from positive to bare metal.

key fob is still not working. It does not unlock the doors or lock them remotely. When you pass the fob through the car door the red light starts to flash on the fob, but the cars immobilizer does not disengage.

We press the start button, the car asks to hold the key against the switch, when we do hold it there nothing happens and after about 45 seconds the sequence times off and the dash goes dark and you try all over again.

Both smart key system fuses are not blown.

key fob has new battery.

when I press the car power button while sitting in the car with the keyfob on my lap the red light on the fob turns on and blinks really fast 5x or so then double blinks 20x while the dash is searching. The red light on the fob stops blinking when the dash times out.

When inside the car the fob starts blinking even when any of the doors are opened or shut. 20 double blinks.

I tested every standard fuse for continuity and did not find any blown fuses.

could anything be interfering with the signal somehow?

maybe I need to just go home come back and try the second key?

 

I don’t think the wires have been damaged due to servicing, I am very familiar with the engine bay I swapped this motor for the 2016 motor 2 years ago and put 40k miles on it so far.

All of the wires in the engine bay are reconnected I gave them a once over after this issue came up and I stay away from the right hand side where the big computers are except for when I checked the fuses after the fact.

There is signs of mice having lived in the car at some point but I saw that 2 years ago and the car was driving completely normal up until last night when it came into this garage.

my thought is maybe somehow one of the computers lost a chip or a capacitor when I reconnected the battery or there is some kind of wacky interference.

What’s really wild is the car is not unlocking with the fob but the car and the fob are able to communicate.

only one other post on this issue and the guy said the dealer said body control module stopped communicating with transmission ecu lol $2900 bucks at the dealer.

anyways my girlfriend lose the key and we towed the car to the dealer and got 2 brand new keys for this car 6months ago.

I mean if we are down to loose wires and mouse damage I think I may be scrapping the car and selling the parts online, this is our business car so it will need to be replaced immediately.

2016 motor only has 75k on it. Brand new water pump and fresh oil haha. When it rains it pours.

 

Wow. So apparently I found the old keys from months ago and was trying to use it. My girlfriend recognized her old cat house key and said these are my old keys. We located the new keys and the car works. What a 24 hour ride literally was about to buy a new car haha.

Edit: car made it home with no leaks. Heat works better than it has in a in a while.