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HELP!!! FOB programming issue

Discussion in 'Gen 2 Prius Technical Discussion' started by Desert Flier, Feb 4, 2020.

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  1. Desert Flier

    Desert Flier Member

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    OK. So I was using my Techstream computer to add a second FOB to my 2005 Prius and the laptop stopped communicating with the car in the middle of the procedure. (I have previously used this Techstream recently and successfully for brake bleeding on this Prius and I've tested it and the data cable today on our 2011 Sienna and it does work). After shutting the Prius off I can not get it to power on and thus I can not get the Techstream to communicate with the ECU. I can't stress that part enough. I've been all over the internet and there are lots of articles but they all seem to assume that I can power up the car and communicate with the ECU. Even if I had a seed code how would I communicate with the ECU? So I'm stuck. I've gotten to a backdoor menu for programming a FOB but ultimately it takes me down the same road and fails to communicate. The FOB will unlock and lock the doors but that's it. What are my options? If I have to send it somewhere for an "All Keys Lost" procedure will the dealer or locksmith be able to communicate with the ECU? The other option I've been looking at is getting a used ECU with FOBS and swapping but I don't want to jump to conclusions yet. I have another vehicle fortunately so I can take my time with this community and work through this if you have suggestions. Ugh.
     
  2. dolj

    dolj Senior Member

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    Is this with the J2534 cable connected, or not?

    This may be a silly question, but have you checked your 12 V is fully charged and in good condition?
     
  3. valde3

    valde3 Senior Member

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    Red thief light is blinking in the dash? What happens when you try to press the power button? Test both key in and out of the slot. If it has a smart key system. Cycle the key button under the steering wheel and leave it out.
     
  4. Elektroingenieur

    Elektroingenieur Senior Member

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    I don’t have any specific suggestions, but I can mention a few sources of information that might be helpful:
    • Section 7 of Toyota’s Smart Key System: Course T973B Handbook, available by subscription to techinfo.toyota.com, under Library > Technical Training, describes the Smart Key System on 2004–2009 Prius cars. Pay careful attention to Smart Start steps 9 through 17, page 97.
    • New Car Features (more info) for the 2004 Prius (NCF555U) describes the Push Button Start System, Smart Entry & Start System, and HV Immobilizer System, on pages BE-4 through BE-47. This information also applies to 2005 models, for which New Car Features (NCF275U) describes only minor changes.
    • The Engine Immobilizer System section of the Repair Manual (under Vehicle Interior) also has useful information and troubleshooting procedures.
    • Bulletin T-SB-0057-18, “Immobilizer and Smart Key Reset” (PDF), describes how the reset procedure works for Toyota dealers. Obviously, you would need another way to receive or calculate a pass-code number, if you need to use the reset procedure, but the bulletin gives another hint, on page 7: the Techstream system may be able to communicate with the relevant ECUs even if the ignition is off.
     
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  5. Desert Flier

    Desert Flier Member

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    I've had the battery on a float charger the entire time and it usually reads between 12.6V-13V on my meter. My cable is a MINI-VCI J2534.
     
  6. Desert Flier

    Desert Flier Member

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    The red thief light is blinking always no matter what I do. When I push the power button with the FOB inserted into the slot nothing happens. If I push the power button with the FOB not inserted into the slot the yellow Key and ! light illuminates accompanied by a long beep. The fob will lock and unlock the doors. I have cycled the button under the steering wheel and it is currently out. I was able to pull up a data page and look at some parameters so there is some basic communication going on between the Techstream and ECU but still unable to power car up. I can see in live data when I cycle the button under the steering wheel.
     
  7. valde3

    valde3 Senior Member

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    Can you lock and unlock the car with SKS (buttons on the front door handle)? So you can get data from ECUs with Techstream? Go to immobilizer (you may need to open and close the door to keep communication up) you may need charger to keep 12V battery up. Check data on stuff like: Immobilizer, check, permit, master key, regist mas code, regist sub code. If last two are 0 then there's no key programmed in the system.
     
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  8. Desert Flier

    Desert Flier Member

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    Car will not unlock with the SKS buttons. I've honestly tried about every menu and back door approach that I can think of. This may be a little over my pay grade haha. Will talk with the dealer again tomorrow.
     
  9. dolj

    dolj Senior Member

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    The car does not unlock by pressing the little black buttons on the door handle or tailgate. This is for locking only.

    To unlock, you touch the back of the door handle to unlock or press the black pad in the tailgate once to unlock. For the tailgate, press the black pad once to unlock. All locks should unlock using any one of these touchpoints. To open the hatch, press once more and lift by pressing up on the black pad at the same time in one fluid movement. If you find this is difficult to do because the tailgate seems too heavy, you need to look at re-gassing or replacing the gas struts. When working correctly the gas struts should counter-balance the weight of the hatch door so lifting it should be more or less effortless.

    If nothing happens, when you press a pad or the back of the handle, check that the "Key" button (under the steering wheel) is in the out position. This button is the SKS deactivate switch. When pressed in (on) the SKS function is deactivated. When it is out (off) the SKS function is not deactivated. Deactivating SKS can be a good idea for when the car is being left idle for any length of time to save draw on the 12 V battery.

    All this is explained in the Owner's Manual. Well, most of it – the bit about the gas struts is not there.
     
  10. Desert Flier

    Desert Flier Member

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    I didn't explain that all too well. What I was implying was that the SKS function wasn't working at all. Only way to lock and unlock the car was via the buttons on the FOB itself. Thanks for the tip on deactivating the SKS function if the car is going to be left idle for a spell.
     
  11. Desert Flier

    Desert Flier Member

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    OK. So this post will be disappointing to those looking to solve a similar FOB programming issue. Nonetheless I wanted to close the post out and not leave a dead end. I ended up towing the car to the dealership and they fiddled with it for several hours. Fortunately the ECU/Immobilizer wasn't bricked but they ended up having to get a seed code (which I expected) and input some additional authorization codes to program two new FOBS with SKS function. My original FOB that had always worked could no longer be used. The tech even had Toyota support on the phone assisting them. So here's my two cents. Programming FOBS can be tricky if you aren't familiar with the process. The instructions on the Techstream are OK but it would help to have someone reading them line by line while you carry them out. The computer will time out if you don't complete certain tasks in a given time frame. You also run the risk of the Techstream having a glitch during the process. It's probably rare but in my case the Techstream stopped communicating with the ECU halfway through the programming procedure. After that, I was dead in the water. I spoke with the tech and it was tricky even for him to get it back online and he has done many of them. Personally I probably wouldn't monkey with the FOB programming feature again but that's just me. To the dealer's credit they flat rated the programming charge at 2 hours and I know they had about four hours into it before they figured it out. So in the end it didn't cost all that much more to get this issue fixed than it would have to just have taken it to the dealer to have a second FOB programmed in the first place. The fee is the same up to five FOBS I believe. Thanks to all who chimed in here with ideas. Another feather in my cap.