2011 Gen 3 Prius Model 3: FOB Startup vs Physical Key Security

Several weeks ago I purchased a used 2011 Gen 3 Prius Model 3. A very impressive piece of engineering.

I have been reading different threads on this site, and appreciate all the advice which is being shared.

This is my first post. If I am unclear, please ask for clarification. I am looking forward to your good suggestions. Thank you for your time.

I have decided to accept some inconvenience regarding unlocking the door and system startup, if it means I will have better security.

1) I plan to use the interior button on the driver's door to lock all the doors and to use only the physical key to unlock the car. I plan to turn off the FOB's ability to unlock the door (currently, the door is unlocked by both FOB proximity or if I press the unlock button; I plan to inactivate both functions).
2) For system startup, I will hold the FOB close to the Power button when I press the Power button.

I spoke to an auto locksmith (not the dealer) who said it is possible to have the physical key copied (using a laser cutter) and that the key will fit on a regular keychain. This is okay with me, since the greater torque, provided by the larger key "handle", will make the key easier to turn after it is inserted in the door lock cylinder.

I have already confirmed that the FOB RFID works as expected. If I remove the CR1632 battery from the FOB the car still starts up, but only when I press the brake and have the FOB near the Power button when I press the Power button. (I did not confirm that I could drive the car, but the display said "Ready". The 12 volt battery seems to be fine, but I have not confirmed the resting voltage.)

I have not decided if I will ask the dealer to turn off the wireless door locking/unlocking feature, or if I will do it myself. I found a thread which describes the procedure. I will update this question after I locate the link.

So in summary, I have one FOB which works well (wireless entry and proximity hybrid system startup). I think the above plan will work well to achieve my goal of security, but unfortunately the second FOB which the seller gave me does not work.

The second FOB, which has the same FCC ID imprinted on the plastic case. The seller said the CR1632 battery needed to be replaced, but that did not fix the problem. I swapped the two batteries between the working FOB and the second FOB. The working FOB works with both batteries, but using both batteries the second FOB neither unlocks the door, nor does it start the car.

The red LED works on the second FOB, so at least some of the circuitry is working. I do not know if the second FOB was immersed during a laundry cycle.

Using the second FOB I cannot unlock the door (neither by proximity nor by pressing the unlock button). The second FOB does not activate the hybrid system.

It is as is the second FOB is no longer "recognized" by the car. I do not know if there is a specific word to describe this process? Is it possible for a car to lose a FOB registration?

So the question is how do I get a second working FOB? My understanding is that since the FOB has been used it is not a "virgin" FOB, so there is no easy way to ask the car to register the second FOB.

However, after reading different threads, my understanding is that the second "non-virgin" may be used if the ECU is reseeded. It is not clear if a auto locksmith the proper credentials can do this.

I believe there is a limit to the number of FOBS which can be registered by each ECU. I do not know if additional FOBS were registered by the first owner, or if only the two original FOBS were used.

I have not been to the dealer, but I am guessing the cost of a new FOB will be high.

I am reluctant to drive the car until I have two functioning FOBs. It is clear that without a functioning FOB the cost to reprogram the car is very high.

Please help, and again, thanks!

 

Hello PriusCamper, ASRDogman, and cnc97 (and future readers).

I am sorry I did not find a way to make the original post shorter. I should have been more clear with my questions, regarding a used 3rd Generation 2011 Prius which I purchased a few weeks ago from the first owner which has one working FOB and one non-working FOB. The seller knew the FOB was not working, but his explanation is that it simply needed a replacement CR1632 battery. (Yes, I trusted him, and did not think of testing the battery from the working FOB in the nonworking FOB.) The trivial explanation is that there was a mixup and that the seller gave me a FOB which was never registered/recognized by the car, but for now I am assuming I have the two original FOBS which came with the car:

My two questions:

1) The RFID system for starting up does not require the FOB to have a working battery (which I confirmed by removing the battery from the working FOB). I am wondering if it is possible for a Gen 3 Prius to forget a previously registered/recognized FOB?

2) The nonworking FOB is not a new virgin FOB. I have one functioning FOB, but want a second one. If there is a sequence of steps which can be used to register the non-working FOB with the car? Is there a way for me to do this, hopefully without Techstream, or do I need to pay an auto locksmith or the dealer?

So the fundamental question is how to get my second FOB working without spending a lot of money?

For me the "coolness factor" of owning a Prius are the motors, the engine, and the traction battery. (The 12 volt battery seems to be a weakness). I bought the used Prius for its hybrid technology, gas mileage, and hopefully lowest "total cost of ownership", not for the car's wireless entry or ability to start without turning a key. I care more about the condition of the car (that is never be vandalized). I care a lot less about the convenience of the door being unlocked as I approach the car, because the car can detect the FOB in my pocket. Other forum members have described their feelings that the wireless system causes more problems than it fixes. For example, in a family with several drivers, it can get very expensive to buy FOBs for each person.

Today, my concerns about security are less important (because for now, the car is safe) and hopefully should not affect your answers to my questions about getting the second FOB to function.

@PriusCamper, please do not concern yourself about why I am worried about vandalism or theft. I simply do not want MY Prius to be vandalized or stolen. Low crime statistics do not make the crime victim feel better.

@ASRDogman, for now I would like to assume the second FOB is not damaged.

To all, I welcome any suggestions for how to get the second FOB to work, is possible, without buying a replacement FOB.

@ASRDogman, you ended your response by asking how I was planning to "turn off" the key FOB functions of locking/unlocking (the doors). Obviously, there is nothing which can be done to the FOB (except to remove the battery), so the question is how to turn off the scanning function of the car.

However, in the following post (by user vincent1449p):

Turn off Smart Key System | PriusChat

he says "The GenIII Repair Manual has instructions to disable SKS without Techstream, I've just tried it and it also works on our C."

@cnc97, I wrote most of this response before I saw your comment. Thanks!

I hope I was more clear about they help I need (getting the second FOB to work). Thanks again, and to all a good night!

 

This thread is getting long, so for future readers I should say I am the original poster.

@PriusCamper, thank you for sharing the possibility of using an eBay service to reset my FOB. I prefer try to find a local business which provides the same service, because I do not want to take the risk that the FOB gets lost in the mail. If the business is in a neighboring state I will have a reason for a road trip. The best strategy may be to buy a virgin FOB, and after that is working, then to solve the problem of the non-working one.

@ASRDogman, thank you for sharing how you use your Prius, and for describing which features you enjoy the most. I agree that for you having the proximity door unlock feature on the passenger side would be useful. I wonder if that is an option which can be activated. Does anyone know? If I am able to accomplish what I am hoping to try then to open the passenger door I will need to walk around the car to use the key to open the driver's side door.

One of my biggest questions when comparing the Prius to a Honda Fit was automatic vs manual transmission. I enjoy driving a car with a manual transmission, because shifting keeps me more connected to the car. The extra cargo capacity of the 2nd generation Honda Fit almost pushed me in that direction.

Yes, the link I provided to Vincent's SKS non-Techstream inactivation procedure is most useful to owners who will not be using their cars for several weeks, or said a different way, most useful to owners who will not be using wireless SKS to open the car doors for several weeks. One reason I am hesitant to try it myself is that I have not found a similar series of steps to reactivate the SKS door unlocking feature. By inactivating SKS I may extend the life of my 12V battery, a clear benefit, but that is not my primary reason.

I have downloaded several PDFs from the 2010 Gen 2 Prius Service Manual, but it is unclear what I am missing. I think it is worth the $20 for two days of access the Toyota Prius Tech Info site. With some luck, if I download all the PDFs then I will find the procedure for reactivating SKS. I will also keep my eyes open for an option to activate passenger side door unlocking.

@ASRDogman, you are correct, only one FOB is needed because only one person can drive at any moment. However, I have read posts from users who suggest having at least three working FOBs. One for regular use, one for backup use (when the primary FOB is temporarily misplaced), and one emergency FOB. Three FOBs may be excessive, as well as expensive, but I think having at least two is necessary. I want to avoid having to pay a lot of money to the Toyota dealer when the ECU needs to be replaced and the two FOBs need to be replaced.

Remember, at the moment I have only one working FOB, and it is still unclear if the second FOB is not working because it was accidentally switched by the seller or if the car's ECU (?) somehow forgot the second FOB. Still searching for similar experiences by other owners.

And finally, the reason I said I thought the 12V "deep-cycle" battery is a weakness is that some owners seem to be reporting the need to replace the batteries more often than I think regular "high current" 12V are replaced. For some fun, I may try to open the hatchback from the interior, something which will be needed if I drain the 12V battery.

It is clear to me that the condition of the 12V Prius battery affects fuel efficiency, because if the 12V battery is not charging well, then more energy is used in the attempt to charge it and less energy is used to charge the large hybrid battery. I saw at least one report which suggested that if a car needs a boost (eg. if the 12V battery is drained) that this may reduce the useful life of the 12V battery. However, the reduced lifespan may be related more to the deep drain and not to the boost.

I need to learn more about emergency 12V booster packs. To optimize 12V battery life is not clear to me if or how climate temperature or driving habits (which affect hybrid battery SOC) affect the 12V Prius battery. Still, so much to learn.

The prices for 12V deep-cycle batteries seem to vary from $200 to $300, but I hope that a $200 battery should last more than a few years.

 

@fuzzy1, in 2017 you posted a response to a member who was trying to find a way to secure his car against people using scanners to amplify the FOB communication between the car and the FOB.

Chinese hackers with proximity keys | PriusChat

Do you think disabling SKS would work, or can you suggest other options, which still add security against the possibility of SKS hacking, but at a lower inconvenience to the owner?

I am still searching for ways to secure my Prius, because if it is stolen or vandalized then I cannot enjoy it.

In general, I am NOT asking forum members to question if the underlying concern is true. If the underlying concern is true, then what are your ideas for solutions?

@ASRDogman, thank you for sharing your opinion that paying the Toyota dealer is the best way to be sure the job is done correctly, even though it will cost more. You are also concerned about the TCO, because you drive a Prius for its fuel economy, you buy 12V batteries for other vehicles when they are on sale, and you do not think it is worth spending the money to add hardware to your front passenger door to get SKS proximity entry to work.

So yes, in the end, I may choose to pay the Toyota dealer to sell me a working FOB. I want to have two.

I am interested in driving my 2011 Prius for many years, and I like knowing how things work. If other friends buy Prius cars then it may be worth if for me to buy Techstream (because I can use the software on several Prius cars). However, before I invest in Techstream I plan to buy an ODCII scanner.