My Gen 4 Prius key fob got stolen. How to deactivate lost one?

If the CPU on your Prius is re programmed and you get new fobs, you don't need the old one disabled, because it won't work your car any more. The car will only open with the new codes/fobs.

 

I don't know if it is the same for the Gen 4. I've only done it with the Gen 3. No reseeding is need, if you have at least one working key fob.

Yes, you need to delete the OLD fob. It is done with Toyota Techstream software hooked up to a laptop with a VCI cable connected to the OBDII port on the car.. The original Toyota system is very expensive. Asian made clones with bootlegged software is available on Amazon for about $25.

When connected to a laptop, do NOT have the laptop active on line. It will ask for your dealer and authorization number.

Purchase a brand new fob from an official on-line Toyota dealer for about $130. The laser cut insert key is a misnomer. It is cut with a CNC mill with key cutting software. Many locksmiths can do this for you for about $25.

Good luck...………..

 

If you plan to do this yourself, or want to know what a dealer or locksmith would do, there are step-by-step procedures in the Repair Manual under Vehicle Interior: Theft Deterrent/Keyless Entry: Immobiliser System: Registration. The Repair Manual is available by subscription to techinfo.toyota.com; its text and illustrations are also in the ChiltonLibrary service, to which the Los Angeles Public Library and many others sponsor access.

Note that keys can’t be deleted individually. Instead, Procedure “D” (Smart Code Erasure) is done to clear all of the registered keys but one, and then Procedure “C” (Smart Code Registration) is done to register each of the other available keys, including any new ones.

Correct. Procedure “E” (Smart Code Reset), which involves a seed number and waiting for 15 minutes, is used only when all of the keys have been lost. This procedure (but not procedures “C” or “D”) requires either dealer or Security Professional access to Toyota TIS or a third-party calculator program, to determine the pass-code number that must be input into the Toyota Techstream software.

 

I'm curious about the level of risk that you are trying to alleviate by deleting the old key fob, you are sure the fob was stolen? Or is it just missing and you aren't sure what happened to it? Maybe you don't want to share the details but I'm imagining a scenario like leaving the fob on a table in a restaurant and when you came back to the table it was gone, something like that. Using that as an example, in situations like that I think people will take something like that on the spur of the moment thinking maybe it can be sold. Later they realize it's not easy to sell and just dump it. Or maybe they are more industrious and sell it on eBay. Either way it seems there is no risk of the fob being used to steal your car since neither the thief or the buyer knows who the owner is. Even if the thief knows it seems extremely unlikely they would advertise that it is a stolen fob. Unless they thought they could sell it to a car thief along with the address of the owner. Or in case of astronomically bad luck whoever got a hold of your fob happened to be a car thief.

Anyway I'm just wondering if this is a situation where the odds may be one in a million that the missing fob will be used to steal your car but you would just feel better not having to worry about it. If so that's fine I'm just trying to figure it out since it seems like it's a lot of hassle and/or expense to delete the old fob. Having a car stolen is no fun as even with insurance there would be a financial loss as well as all of the hassle. But it if was me personally I would take that risk if it was an extremely unlikely occurrence rather than go through all of the research and hassle that you are going through but maybe I'm just lazy.

 

Experiences reported here with such cables and their software and firmware vary; some work with most or all functions of the Toyota Techstream software, and others don’t.

Keep in mind that if the smart key or immobilizer system is left in a non-working state, the certification ECU and ID code box may have to be replaced. The latter is (by design, to deter auto theft) accessible only after removing the entire instrument panel and the air conditioner unit assembly, which requires discharging the refrigerant.

I recommend the version of Toyota Techstream available with a Professional Diagnostic subscription to techinfo.toyota.com ($65 for two days) and the MongoosePro MFC2 vehicle interface cable.

The Tactrix Openport 2.0 device also seems to work with fourth-generation Prius cars—it communicates with the ECUs on mine well enough to do the Health Check—but I haven’t tested it for security reprogramming.

Toyota writes in Smart Key System: Course T973B Handbook (available by subscription to techinfo.toyota.com), “A used key can be registered to a new vehicle only after a Smart Code Reset, but even then, only the first key registered will get the new vehicle ID.” As I noted above, however, a Smart Code Reset requires more than just Techstream: you have to be able to respond with a valid pass-code number for the seed number it shows.

 

In the case of deleting all but one key fob and the possibility of deleting the active one, I don't fully recall. I believe that it is necessary to hold the chrome color Toyota symbol up to the start-stop button to start the procedure.

I can't confirm, but it would be more likely than not, and if the algorithm was properly design, the key used to start the procedure would be the one that is retained.

Anyone who has done this procedure more than the one time that I have, please comment or confirm.

 

Hi. can you share how you resolved your key fob situation?
I have a similar but worth situation, I just got my 2016 Prius Eco delivered from the auction,.. oops both keys are gone.
Any suggestions?

 

Toyota has provided the Smart Code Reset function, which I mentioned in post #4, above, for just this scenario.

You’ll also need at least one unprogrammed key (electrical key transmitter sub-assembly), part number 89904-47530, but preferably two; and for the mechanical lock in the driver’s door handle, either the services of a dealer or locksmith, or a new lock cylinder set with matching key blades, part number 69005-47230. (See catalog Figure 67-12, Lock Cylinder Set.)

 

I got into the same situation, bought a car at an auction and the keys were missing upon delivery.
Prime 2017.

The most interesting thing is that the car left the auction with the windows closed, this can be seen in the photo when loading. And the car arrived at its destination with two front windows down and without keys. The delivery service claims that there were no keys, and the windows supposedly can be opened without a key. But on all my previous Prius that I had, a key was always required, so I think for Prime 2017 it is also impossible to open windows without a key. So the key was there and it was stolen on the way.

I'm sure that the my shipping company is deceiving me, but I have already resigned myself and just want to solve the problem.

Thanks for the useful information above.

If I understand correctly, in my case I need a "Security Immobilizer / Smart Key Reset"
Security Professional* Subcription
But it required "Current member of the NASTF Vehicle Security Professional Registry", which, as I understand it, I cannot get it. At least NASTF website won't even open.
So I have a problem of gaining access to the Techstream TIS for 2 days as a membership is required which I do not have.
Or I'm wrong?

I bought a new key from Toyota TRANSMITTER SUB-ASSEMBLY, ELECTRICAL KEY 89904-47790 and I have the original Mongoose cable that I bought a long time ago, about 7 years ago, which I haven't used in a very long time.

Any help on any terms would be glad.

 

For an authorized copy of the Techstream software, the source depends on where the car was originally sold. If it’s a Prius Prime car from the U.S. or Canada (model code ZVW52L-AHX_BA), use the Techstream software available with a Professional Diagnostic subscription to techinfo.toyota.com. If it’s a Prius Plug-in car from Europe (model code ZVW52_-AHX_BW), use the Global Techstream (GTS) software available from toyota-tech.eu. Unlike the Security Professional subscription you mentioned, these are both available to anyone.

If your Mongoose cable was made for use with Toyota vehicles, the software should work with it, but you may need to install the latest device driver and J2534 library from Drew Technologies; scroll down on that page to see the downloads for their older products.

One you have a working Techstream system, to do the Smart Code Reset procedure, you still need to be able to respond with a valid pass-code number when the software shows you a seed number. Unless you’re a locksmith or in the automotive business in the U.S. or Canada, you won’t be able to meet the NASTF requirements to get a Security Professional subscription from Toyota. Third parties have reverse-engineered the system, however, and sell calculator programs or the service of computing pass-codes. I don’t have one to recommend, but you can find many offers for these by searching the Internet for “Toyota pass-code.”

 

Thank you so much.

 

You're going to some serious extents to avoid going to the dealer...

That's like an hour max thing and you're sure that nothing will be messed up after. With the techstream, you need login credentials to do the seed request and that request has to be sent to at least two people (manager, etc) in the shop, they then have to confirm it, which sends you to the seed number page and then you can proceed with the reset. It will erase ALL keys and the tech then registers whatever remaining keys you have. It obviously doesn't replace the manual key to unlock the car...

 

@amzerox's PriusChat profile says his location is “Moscow.” If that’s Мoscow, Russia, consider that Toyota dealers there might not be willing or able to provide this service for U.S.-specification vehicles.

As I explained in post #4, the Smart Code Reset procedure is needed only if all the keys have been lost. If at least one working key is available, the Repair Manual (more info) says that only a Techstream system is needed to erase keys or add new keys.

As I understand it, those administrative controls can be bypassed by paying a small honorarium to any of the third parties who offer pass-code calculator programs or the service of calculating pass-codes on demand.

 

It's been a while, I don't think I ever got a car with remaining keys.