Check engine on new 2021

Your welcome & good luck.

Talk to a Pest control specialist, might be the first step and likely will provide you with a correct application.

Some products on Amazon.

Exterminators Choice - Rodent Defense Spray for Cars and Trucks - Non-Toxic Deterrent for Pest Control - Repels Mice and Rats - Vehicle Protection - Safe for Kids and Pets (32 Ounce)…

https://www.amazon.com/dp/B01DTBOV06?uh_it=87d630719f7b96bb29acacff45fd172b_CT

$32 Grandpa Gus's Extra-Strength Mouse Repellent Pouches, Cinnamon/Peppermint Oils Repel Mice from Nesting & Freshen Air in Car/RV/Boat/Garage/Shed/Cabin, 1.75 oz (Pack of 10)

https://www.amazon.com/Grandpa-Guss...s=bitter+apple+rodents&qid=1630692004&sr=8-20

 

I got and have used the Rodent Defense linked above, just in case. No rodent issues in the 2 years since.

 

I live out in the woods - mice, voles, chipmonks, squirrels, deer, bear, etc.

I use peppermint oil, put it in a fine mister and spray it on the back of the firewall about once a month, where they usually start chewing for nesting materials. So far, no rodents. You can also put a few drops on the cabin air filter. Smells like chewing gum.

I also bought 2 ultrasonic transmitters that use batteries, one in the glove box and one under the hood. Runs about 45 days on 3 AA Lithiums. Has flashing led lights and a ultrasonic speaker.

 

OP UPDATE: thank you for all the comments and knowledge!
So Found rats nest Chewed through the O2 sensor wiring harness 38 dollar part but required engine tear down total cost for insurance $2783 most was labor. I have had exterminator deploy bait traps all around the property with one in Driveway right next to the 4RUNNER abd Taco so far since deployed we have poisoned or killed three rats one was nesting in the neighbors car (infinity). And using rat spray repellent on the wires for now just got it back on Friday took few weeks no adjusters available , we have never had rats before but the City is doing major construction and messing with sewers. I’m ordering an ultrasonic thingy who knows. We need a class action to get Toyota to not use food (Soy) in the wiring ugh.

 

I know this is an old post, but to OP, do you know what the CEL code this was?