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Comment by chasd00 | Hacker News Reader

Tangent but I have a 2016 Toyota 4Runner. Great car and fits my family and needs perfectly. The key fob broke so I needed to get a replacement, I got a blank and had a locksmith cut and program the blank. He must have not done it right because it worked and then I got stranded cause it must have lost its pair to the car or something. Nothing wrong with the vehicle, the engine wouldn’t start because of the key. I do road trips through the desert SW and other remote places, if I have the key I need the car to start no matter what. I really don’t want my keys to require a battery either. I wish there was a way to bypass the rfid/BLE or whatever it is.

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If you even rarely get into situations you describe, saving on a freakin' key fob and not going via official dealership is supremely... not smart.

What you describe would be exactly reason #1 I would immediately say to anybody on topic of why not saving desperately on such a thing, despite never being in such situation myself.

Sometimes learning from other's mistakes should be enough. No, mostly it should be enough.

Difficulty: dealership replacement keys are like $500/each believe it or not.

Did you get a genuine key? I never had one fail on me.

The immobilizer is the single best piece of technology for preventing car theft. If you create a backdoor for bypassing it, you'll end up like Hyundai/Kia which decided to sell cars without the immobilizer in recent years and which have turned into a joke in the minds of potential customers.

It does not require a battery in most cases and is separate from the keeloq system that controls your car's doors.

The Stellantis systems I’ve worked on have a nice feature that there is a battery for the proximity use, that you can keep the key in your pocket and press the button to run the car, as long as the key is within the four or five proximity sensors you are fine.

When that battery dies, you can press the directly to the start button and it uses a “receiver powered transmitter” RFID close proximity to start and run the vehicle.

Most people don’t know this, so when that battery dies they panic and suffer.

This technique of pressing the dead key to the starter button works for quite a lot of brands, not just Stellantis vehicles. Always worth trying if you are in a "keyless" car with a dead key fob battery.

In my experience virtually everything made in last 15 years will either support this RFID backup or have a spare physical key hidden inside the keyless fob.

Lots of them will even let you press the dead key against some part of the exterior to unlock the doors too.

What is funny to me is that before the proximity and push https start… the keys had RFID and an antenna at the lock cylinder anyhow.

They just left that same antenna in place (in Chrysler+ anyhow, called SKIM) now as a backup instead of the primary.

You can disable the RFID by manipulating the right bits in the ECU’s anti-theft EEPROM. Something that’s done with imported engines from Japan for sports car engine swap; they usually come with wire harnesses and ECU but no key. I know how its done for the imported 3SGTE engine ECU… I’m sure it’s not too different for the 2013 4Runner. Though, Toyota makes some newer ECUs nearly impossible to open without damaging the circuit board and anti-theft bypass requires physical access to the EEPROM.

Edit: RFID should not need battery…you can reprogram your own key by jumpering the correct OBD2 pins..process takes about 20 minutes…

for my 2016 Mazda, the keys do not need a battery to operate.

you instead need to hold the fob up to the start button and it will work passively, rather than just being in the car normally. Glad they still give manuals with cars as I had to learn that without service.

There are three systems to the key, the doors and remote start, the “passive entry” which requires the battery, and the backup RFID you’re talking about.

Get ready for key subscriptions!

Please connect to the internet to start your car

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