size comparison of transponder chip inside the car key

Toyota Corolla Immobilizer

This article was made as a companion for the Toyota Corolla Immobilizer Reset Service we offer for the 2005-2007 Toyota Corolla, but it could also be helpful for you if you own one of those models and recently replaced the ECM with a used or recycled one and your car is not starting.

When you replace the ECM of these Corolla models and the replacement ECM is not brand new or at least was not previously reprogrammed, the engine won’t start because the used part has in memory the old key codes of the keys from the donor car. Those codes will not match the codes of your keys and will create a no-start situation.

Identifying the situation

Please note that with “no-start“, I mean that it cranks ok (the starter motor runs), but the engine does not start. If instead, the starter motor does not run either, then the problem is not the immobilizer and could possibly be an aftermarket alarm system that comes with many of these Corollas. The rule is; an immobilizer problem will cut injection and/or ignition but will let the starter motor crank. A problem with the anti-theft security system (alarm) will cut the starter too. If the problem seems to be the alarm, We are providing some instructions for that situation too under the heading “The Alarm system” further below on this article.

Your car may include one or both of the following:

  1. Immobilizer system (factory installed): Disables injection and/or ignition by internal means (ECM)
  2. Alarm / Anti-theft system (aftermarket installed): Disables starter. May disable injection and/or ignition by external means (Wiring).

What to do (immobilizer)

Ok, the ECM was replaced and the car won’t start? We have two possible solutions here. You may either; (1) perform an immobilizer synchronization (sync from now on) between the replacement ECM and the immobilizer system of your Corolla or, (2) if that does not solve the problem, you may use our corolla immobiliser reprogram service to reprogram the immobilizer of the replacement ECM.

The first solution above (sync process) may fail to do the trick if; (1) the memory chip in the ECM where the key codes are stored is full (it has a limit on how many key codes can be registered), (2) the memory chip is defective or damaged or (3) the ECM is damaged.

The good news is that the first solution (sync process) is free and most of the time it solves the problem and even when it sounds kinda complicated, it is a very easy to do procedure, and you can do it yourself with just a bare paper clip. It is explained in detail below.


The Sync Process (Free, Do it yourself)

To sync your replacement ECM with your car’s immobilizer system you will need to jump two connections in the OBD diagnostic port terminal for 30 minutes with the car key in the “ON” position. That is, all the way forward, right before starting the engine.

Because the ignition and all systems will be turned on, but the engine will not be running, you need to make sure that your car’s battery is fully charged or you must connect a charger to the battery while doing the sync process to ensure that voltage will not drop. If the voltage drops considerably (below 12 volts), the process must be restarted all over again and wait another 30 minutes. Also, it is important that if you are going to connect a charger, it must not be in “trickle” mode and it must be of good quality in order to avoid electronic noise from the charger that can negatively affect the sync process. If you do not have such a charger, then it is recommended that you fully charge your car’s battery first with any charger and then do the sync process, but do not use the charger WHILE doing the process.


A) First, locate the diagnostic port. It is under the dash in the driver’s side under the steering wheel, near the hood release lever. It is a dual-line 16-pin connector (8+8). See the illustrations below as reference.

Pinout of the OBD port

OBD Port location


B) Now, with the engine off and the keys in “off” position,  jump connectors #4 and #13 of the diagnostic port by using a bare paper clip. Below are example illustrations.

Jumping the pins 4 and 5 of the OBD port 1

Jumping the pins 4 and 5 of the OBD port 2


C) Next, with the paper clip in place, turn the key all the way forward to “on” position (ignition on) right before engaging the starter and leave it there for 30 minutes.

Different lights in the dash panel will start flashing. This is an indication of the process going as expected. If lights don’t flash, then something is not working as expected and you should start over. This not happening as expected can be caused by a poor electrical connection in the jumper you made or if jumping the incorrect connections of the OBD-II diagnostic port terminal. Make sure you are using connection #4 and #13 as instructed previously before proceeding. Below is an animated GIF of what it should look like when it is working correctly, so you can have an idea.


Dashboard flashing random lights when doing sync


D) After 30 minutes, turn the key to “off” position and remove the paper clip from the diagnostic port. After removing the paper clip, you may attempt starting the engine. It should start at this point if the ECM and everything else is good. If it does not start, you may send us your unit so we can program it.

The Alarm system

If the problem is that the starter motor is not running (not cranking), but all electrical systems seem to be right and the battery is charged, then you should try to reset any aftermarket alarm or anti-theft system if any (not to be confused with the immobilizer system). The ECM, good or not, will not prevent the starter from engaging. The immobilizer system will disable injection and/or ignition, but not the starter. So if the engine is not cranking when you try to start the car, it is not necessarily the ECM or the immobilizer system in most cases.

What happens in most cases is that any aftermarket alarm or anti-theft system will need to be reset if the car battery is disconnected longer than a specific time, usually in minutes. In those cases, it is this aftermarket security system that is disabling the starter.

Some Corolla models come with a security light that serves as an indicator and it is a button at the same time. Below is an example illustration:


Corolla security light


In most cases, to reset the alarm you may try arming and disarming it with the remote control provided for it (key fob). If that does not work, then try the following:

1 – Insert the key and turn it to on position, but do not start the engine.
2 – Push the red security button (picture above) twice.
3 – Now start the engine.



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  • Andrea Bailes says:

    It was interesting to find this article as I just recently purchased a used 2006 corolla and was only given one master key. This is the only key I have for this car and they did not give me the code. Can a dealer still make another master for me (using the one I have) even if I don’t have the code?

  • admin says:

    Hello Andrea. Thanks for writing.

    Yes, the dealer should be able to make a new key with your master and the car’s VIN number. The problem for the dealer is when the master key is lost.

    The VIN number of the car, the pin number (seed) and key codes are stored in the ecu (car computer). In case that the master key is lost, then the ecu must be reset (as explained in the article above) for it to learn new keys.

  • Daniel Soto says:

    I just received the Toyota ecu you serviced this week. Now it works fine with my keys. Just wanted to thank you. I saved a lot as the dealer quoted a lot of $$$. About the issue that we were talking about, with the check engine because of the VIN number, I went to the dealer and they set it for free as you adviced to do. I will promote your service (as I am doing now) here in my area. Thank you very much!

  • admin says:

    I am glad you brought your car back to life. It was a pleasure helping you.


  • Jan says:

    My father bought a Toyota Corolla 2006 S model two years ago from US. He got only one master key with remote controller.
    He´s living at Slovakia and wants to make an duplicate key but our dealer of Toyota said him that they have no software for programing of this key which is needed for Toyota from US. Because cars from US market are different than cars from European market. Further more at Toyota Slovakia they told him “there is exists some instructions for self-programming of this key.” Could you advice me if instructions like this does exist or what can he do when he wants to get this key.

    P.S. if it is possible to self-program the key and u have the instrustions could u send me them. Thank you


  • admin says:

    Hello Jan.

    About the keys from USA being different from the European ones is true. Codes change.

    About programming a new key, it is easy and simple, provided that you have (1) an USA key of your model and (2) the key is blank and unused.

    You can do this procedure either before or after mechanically cutting the key.

    You might want to revise and practice the procedure before actually doing it, as it have a few steps that each one have a specific time frame.

    It is a s follows:

    1 Take the master key you have and insert it into the ignition switch. The master key should be black colored, not grey.

    2 Turn the key to on position and before 15 seconds, press and release the accelerator pedal for exactly 5 times.

    3 Now, before 20 seconds, press and release brake pedal for exactly 6 times.

    4 At this time you can remove the master key and within 10 seconds, you must insert the new black key to be programmed into the ignition switch.

    5 Next, before 10 seconds, press and release the accelerator pedal just once.

    6 Wait a few seconds, then remove the new programmed master key.

    If you want to program another new key, you must insert it in the ignition cylinder within 10 seconds after the above procedure and press and release the accelerator pedal only once and wait a few seconds before removing it.

    Test all the keys you programmed after finishing.

    You can program up to 7 keys using this method. After that, the ecu must be cleared to accept new keys.

    Best regards.

  • Jan says:

    Hi admin.

    Thank u for your response a for the instructions. That is the matter what I want to ask you.
    I found some instructions before you sent me yours on

    Add Duplicate Key:

    1. Simultaneously depress and release brake and accelerator pedals 1 time.

    2. Insert existing master key into ignition. Do not turn the key from the OFF (LOCK) position.

    3. Within 15 seconds of inserting the key, depress and release the accelerator pedal five times.

    4. Within 20 seconds of completing the above step, depress and release the brake pedal six times and
    remove the key.

    5. Within 10 seconds, insert the new key into the ignition.

    6. Within 10 seconds, depress and release the accelerator pedal one time.

    7. After 80 seconds the new key is registered and the security light will go off.

    8. Remove new key and depress and release the brake pedal 1 time.

    Steps 2-7 are completly the same like yours steps (1-6). But step 2 (in my instructions) is different in position of master key.

    So which position of master key is correct and should be done the steps 1 and 8 (in my instruction) as well? Because my father already did whole process according to steps above but nothing happend and master key was in OFF(LOCK) position.

    And secondly: I was reading on forum of toyota that during the self-programing can program get frozen and ecu have to be replace. Is that right???

    P.S. I hope that your instructions will be work.

  • admin says:

    Jan, we have done it with the key in accessory/radio, not on ignition position, so I guess that for the process being taking place, it will be the same as ignition circuits will be powered off. Depressing both pedals might be some type of reset before entering the programming/erasing mode. Ours, worked OK without that step.

    I recommend that you first try the all key erasing method, as you only have one key, then do the steps to try to program the new one.

    If still nothing happens after trying both instructions (here and the mentioned site), then it might be the case that (1) the key being tried to program is not compatible with the transponder on your car or (2) for some unknown reason, your ecu is not accepting any more keys even after the process of erasing all keys.

    It is important to notice the flashes of the security lamp, as per the instructions in the site you posted above, as a guide for knowing if the process is being working. If for some reason it doesn’t flash as expected, something is wrong, either with the ecu or the new key.

    I assume that the car is working with the unique key you have, so I rule out the rest of the circuits like the ring antenna and the key lock transponder circuit.

    About dealers, they usually replace the ecu if they don’t have the equipment for resetting the ecu. We do reset the ecu with an eeprom programmer and the correct file for writing on the security chip, which is located in the ecu circuit. A little bit of a technical job.

  • darwinl eal says:

    buen dia ya veo que tienen amplia experiencia com la materia y queria pedirles asesoria.tengo un toyota corolla 2006 y suplante la ecu el inmo y las llaves todo nuevo de caja. programe las llaves y todo bien el carro prendio perfecto. pero tengo un codigo p0630 que me dice que el vin no ha sido programado .cual es el procedimiento para este caso y como se realiza con el tester inteligente gracias..

  • Richard says:

    Hello Darwinl.

    That will always happen when you replace the Corolla ecu for a new one. The new ecu does not have the VIN number on its memory, so it will have to be entered on a certified dealer or using a Toyota specific application with the capability of entering the VIN number, like Techstream. That’s a common issue when replacing the ecu, but there is no malfunction at all.

    If you don’t do it right away, don’t worry, as the check engine light and P0630 will be all to it. Apart from that, all systems, including the immobilizer will be working ok. You won’t have any problem. When you have any spare time, you can go to a dealer near you to enter the VIN number. In some dealers it is a free job, while in some others they will charge a small fee about $40.00 – $50.00. It will all depend on the dealer, but it is a 15 minutes job.

    Best regards,


  • KABELO says:

    I had immobiliser in my 96 corolla 4afe removed,it was starting okay for a while now the ecu light does not go on and the car just cranks but won’t start.What could have gone wrong?The ecu looks ok, Somebody please help,I’m at wits end

  • Guest says:

    Hello Kabelo.

    Thank you for writing 🙂

    After the immobilizer was removed, for how much time did it start ok before the ECU light went on and stopped starting?

    I wonder how did the immobilizer was removed. In all Toyota models I have seen, the immobilizer can be reset or can be reprogrammed, so it does not look for transponder keys, but it is never completely removed. There is always a code working on the immo chip.

    If it was the second option above, then the key amplifier (ring antenna circuit in the key cylinder) must be disconnected and if a separate immobilizer box, known as immobox or transponder ecu, it must also be disconnected.

    I reprogrammed once a 1998 Toyota Camry so it does not look for transponder keys and it worked fine the whole day. Next morning, it did not want to start. After the key antenna amplifier was disconnected, everything was working fine again. In this case, the immobox was not present.

  • soon jung says:

    thank you very helpful,but my car 2005 corolla ce does not set alarm,neither security light flashes or stay on when not set(disarm)it is off,please sr our family need your expertise

  • martin says:

    changed my starter motor on my 1998 corolla but the problem was a worn barrel so got new set from brakers ie immobleiser key barrel now car will not read turns on but will not fire

  • Mace AP says:

    Just replaced ECU(used)on 02 Corolla Runx,engine cranks but doesn’t start, security light flashes, can anyone please help, How can i bypass the immobilizer to kill the security feature so it wont search for the transpondent key.

    many thanks for any assistance.

  • Guest says:

    You will need the ECM to someone that can reprogram the ECM to accept the keys. A Toyota dealer should be able to do it.

    One thing you may try your self is a trick for synchronizing the used ECM with the key codes in the immobilizer system. The picture below describes it. Take in account that the vehicle battery must be fully charged or connected to a boost charger, because the process takes almost half an hour with the car switched to “run” position and the engine off, which will drain a weak battery. If the process is interrupted even slightly because of low battery, it must be started over and wait 30 minutes more again. So please make sure about battery charge.



  • Jason Gallardo says:

    Regarding this issue, I have something that’s a variation to this issue….my wife’s friend has a 05 Corolla that has a
    intermittent starting issue.
    -key in ignition (black key)all lights work, radio, ect. but motor will NOT crank at all, lights do not dim, so it’s not a Battery or Alternator issue as their family mechanic said the electrical system checks out perfectly.
    She had heard to cycle the Key On Key Off 5 times and it would work and still is intermitten, can you help?

  • Guest says:

    Hello Jason.

    Does the car has an alarm that cuts starter? That is mostly the problem in these cases, as the immobilizer disables ignition and injection, but do not disable the starter at all. With the immobilizer set, the car will crank until depleting the car’s battery, but the engine will not start.

    Your problem must be in an aftermarket security system (alarm) that could be installed in the car or in the starting circuit wiring per se.

    If the security system is the case, try resetting it. If that does not work, you should search for defective components in that system.

    If no security system, then you should check the starting circuit components with the provided diagram in the link below. It is composed of the starter itself, some relays, some fuses, its wiring and the ignition switch, which reminds me, that a defective ignition switch tends to do that problem too.

    I hope this helps,



    2005 Toyota Corolla Starting Diagram:

  • Jason Gallardo says:

    ok Richard, I have some more info from last night and her car.
    It does in fact have a Factory Installed Toyota alarm.

    She said that when the corolla decides it’s not going to start:
    – all the lights, radio work
    – when she turns the key, NOTHING happens as in: No engine rotation, no lights dimming.

    AAA tow truck driver shows up and she says “he tapped on something right above the starter” and the car started, so he left….as I was driving home the car completely shut off and I called AAA again and they towed me home. Same issue as all the lights and radio worked, but the motor wouldn’t rotate when I turned the key”

    In my honest opinion, regardless of what their mechanic had said about the electrical being 100% ok, this seems to be leaning towards a “Starter” or “Starter Solenoid” issue? Yet, why would the car shut off while she was driving???

  • Guest says:

    Exactly my thoughts. The starter may be intermittent, but it won’t make the car to shut off by itself.

    If it would only be a starting problem, I would say it is the starter itself, but more commonly, the ignition switch.

    But, since the car is shutting off by itself, the problem seems more to be in the security system. Those systems normally send an ignition off signal, along with a starter cut off signal when triggered. If it is so, triggering the security system could be caused by a malfunction in the system itself or intermittent wiring. Reminds me the systems that turns the car off after a few minutes if it is hijacked.

  • wanito says:

    i have a situation on a vehicle has lost keys and no spare key on the immobilizer type too
    i order the new keys and there 2 keys has arrive and can you please to advise me for
    how to i programmed it without the original key because i dont have left the original one
    also i don’t have programmer tools
    thanks i appreciate your reply on its
    details of vehicle below:
    model :BDG-XZU508V-RETMA
    engine: NO4C-TH 4009ml
    frame : xzu508-0004460

    thanks again
    with many thanks

  • zilog357 says:

    Hello Wanito. I haven’t work on those models, but all Toyota models I know, if all keys are lost, the only way of making a new key work is by taking the eeprom chip out (desoldering it) of the immobilizer unit, reprogramming it with the corresponding “virgin” file and putting it back (soldering) in the circuit. I am sorry, but without any master key, all the easy methods (by using accelerator and brake pedals) will not work.

  • Cedar says:

    Hello, I just bought a 2003 Toyota corolla manual transmission. I’ve had one day. the car requires to push what is actually the mirror button ( valet button? ) and hold clutch to start. the mirror button has now been pushed right in and I’m also seeing another wire with a switch on end of it but is just hanging. I can’t start car now. I don’t have mast keys it seem there are only valet keys? They don’t have plastic on them at all just all metal keys. How can I fix myself ?

  • marsha says:

    Hello. I have a 2008 carolla axio, push start. It is not starting. The engine cranks then shut off. It was scanned it states immobilizer error but the experts can’t seem to fix it…it about a week now..what do u suggest?

  • David says:

    My Toyota Yaris ’08 has a perceived immobiliser problem as it doesn’t recognise the only key’s transponder code and refuses to start fully. However after disconnecting the battery for a while it then recognises everything as it should and runs errorlessly until the next time?
    Does anyone have any sage advice please.

  • Archi says:

    Hi I have a 07 Camry v6 I had a check engine light on for the camshaft position sensor. Car was running fine one day I got home turn the car off the next morning I tried to turn it on and it just turned over. Not sure what is going on I tried scanning the car with obd2 scanner and it’s having a problem connecting to the car. I’m thinking it’s the ecm or Immobilizer. Please help thanks!!!

  • Rob says:

    Hi’ I have Toyota corolla 2005 . when I insert the key. security light doesn’t go off , vehicle does crank but it won’t start . I have change battery inside the key but still ,even if I press close Or open batten on the key it doesn’t respond . please advice can a build in immobilizer be removed .please help . thank you

  • zilog357 says:

    Hello Rob. Looks like the immobilizer system of your Corolla needs to be serviced. It can not be removed, as it is part of the ECU internal programming itself and does not rely on any external part that can be removed to deactivate it.

    Most of the times (99% in my cases), it only needs the immobilizer to be reprogrammed (some call it “reflashing”). If reprogramming does not solve the problem, then you will need to look at the other immobilizer system’s components.

    In Toyota Corolla’s sold in USA, there are two variants, one with an external transponder ECU (Immobox) and other without that box. So the Corolla immobilizer system components in order of which one fails the most to the less are:

    The immobox (not all models)
    The ECU (Engime Computer)
    Transponder key
    Ignition switch antenna and amplifier (all in one box)

    Programming needs a specialized tools for your Toyota model or doing it directly with an eeprom programmer and the file needed to be written in the chip. If using an eeprom programmer, you will need to reprogram the chip in the immobox if present (IC900). Otherwise, the chip in the engine ECU is the one to reprogram. For programming or removing the chip you may see the following articles:

    I am not sure of what ECU number you have, but here, many ECUs can be re-synchronized with the immobilizer system by jumping two wires in the OBD diagnostic port. The information on this is in this same article.

    I hope this helps.

  • sanoe Mohamed says:

    I want to know how to program Toyota smart key

  • Alan says:

    After resetting the Immobilizer, car will start accepting the new key. It could be original master key or a brand new key. From other comments, you said
    “if all keys are lost, the only way of making a new key work is by taking the eeprom chip out (desoldering it) of the immobilizer unit, reprogramming it with the corresponding “virgin” file and putting it back (soldering) in the circuit.”

    But why is method doesn’t work for new key?

  • zilog357 says:

    Hello Alan. If the key is a compatible key, it should work. I am no longer working with keys, but I have successfully done that with keys for the Rav4 and Corolla models. Have you considered maybe having problems with another area of the immobilizer system? What model is it? Are you using the correct virgin file? Do you have keys that are already working in that model?

  • Alan says:

    Hi Zilog357,

    Maybe I didn’t make my self clear. You said the program the “virgin” file is the only way to make the NEW key work, which means there is no other way to do it.

    I want to try your method in your article (jump connectors #4 and #13) to reset the immobilizer, and register my new key, because I think the ECU doesn’t care if the key is new or old, as long as the key can emit the RFID signal. Please correct me if I’m wrong.

    To answer your question, I have a 2005 corolla and my immobilizer system was working fine before I lost my keys. I didn’t try to virgin my ECU. I lost all my original keys, and have purchased a new un-programmed key from the dealership. I saw the post talking about how to virgin the ECU but it seems too much work to me.

  • zilog357 says:


    “I want to try your method in your article (jump connectors #4 and #13) to reset the immobilizer, and register my new key”

    Unfortunately, that will not work. That process is to synchronize the engine ECU with the immobilizer ECU. It does not cover the key.

    ” because I think the ECU doesn’t care if the key is new or old, as long as the key can emit the RFID signal”

    The ECU doesn’t care as long as:

    (1) The key is compatible – There are different algorithms among different models
    (2) The key code is already registered in memory – The RFID transmitted by the key will contain a code. If the code is not registered in the eeprom chip, the system will reject it and the engine won’t start.

    If your key is brand new and it is compatible with your Corolla, then it will fall in #2 above. That is why the eeprom chip will need to be virginized. Virginizing the eeprom will erase all the existing codes, which is good because it has room for about 8 keys only and will put the ECU in “auto-register” mode, which is a mode where it accepts and registers the first three keys used to start the engine after the eeprom is virginized. Then it will only start with the registered keys.

    “I have a 2005 corolla and my immobilizer system was working fine before I lost my keys”

    Then in your case, a new key a virginized eeprom is the way to go.

    “I saw the post talking about how to virgin the ECU but it seems too much work to me.

    And I don’t blame you. That is way too much work for a simpler task. For that, I just put a micro-pincer wire in each lead of the chip and reprogram it without desoldering and soldering back. The micro-pincers need no soldering. To program it, I use an eeprom programmer. The extra stuff in the video is to do it without having the needed tools I guess.

    So you will either need to reprogram the eeprom with a virgin file or replace the eeprom with an already virginized eeprom. If you don’t have the programming equipment, but can replace the eeprom chip (desoldering the old out and soldering the new in) then the second option is best for you and I can provide an already virginized chip.

    If you don’t have the skills or the tools and/or the programming equipment and prefer to send your ECM to be virginized, contact me privately by using the contact form in this website. I can offer a free option.

    Kind regards,


  • Warryck says:

    Hi i have swaped the 7m in my 7mx83 for a 1jz gte vvti that has an immobiliser.
    I need a wiring scymatic for an 01 Toyota crown athlete, and a solotion for the immobiliser..
    Hope u can help pleaser,and thank you,

  • Mike says:

    does this ecu paper clip reset work on both Petrol and Diesel models, or just Petrol.
    Many Thanks

  • zilog357 says:

    Hello Mike.

    Unfortunately, we work only we petrol engine cars. It works perfectly on petrol Toyota models, but I have never tried that in diesel engines.

    My guess is that it should work the same in diesel models, as what it does is putting a “vendor reserved option” pin (pin 13) to ground (pin 4) to activate a function. So pin #13 is reserved by the manufacturer, in this case, Toyota, for installing custom functionalities. Diesel engine models are no exception.

    You know, the key to knowing if it is working correctly in petrol engine models is by checking the dash when the clip is connected and the ignition turned on. If the dash lights flash randomly, then it is on its way. So if you do this to a diesel Toyota model and see the flashing lights right after the jumper is placed and the ignition switch is turned on, then it is working and you can leave it like that for 30 minutes to complete the process. If you were just testing whether it works or not, you don’t need to wait the 30 minutes and can turn the ignition off and remove the jumper anytime and nothing would be broken.

  • shaun says:

    I have a 2013 RAV4 just got new immo . Does it auto accept new keys after. 4-13 jumper is removed!

  • zilog357 says:

    If it is brand new, then it should accept the new keys even without doing the jumper thing. But if it is not new or it is new but not accepting the keys, then yes, the jumper thing should do the trick.

    Remember to make sure that the battery is fully charged. Also, if the dash panel lights are not flashing while waiting for the 30 minutes, then something is not working, like for example, the jumper not making good contact.

    I hope this helps.

  • shaun says:

    Ok before I did jumper immo light was off. After it is flashing . Is that good or bad? Now what do I do? Is there any combination I need to do?

  • shaun says:

    Zilog357 I did the jumper twice on new immo how do I add keys to a 2013 RAV4? Think I need to take to a locksmith?

  • zilog357 says:

    Besides the flashing light, did it start with any of the keys? Did you try all the keys you have?

    The jumper process is for adapting the immobilizer system of the vehicle to a used ECM. If a brand new immobilizer (immobox) was installed, it is not supposed to need the jumper process. I suggested doing so because of what you described that you installed a new immobilizer and it was not starting. This would reset everything and rule out the possibility of any code in the immobilizer.

    After the immobilizer is either reprogrammed or replaced by a brand new one, it should be in “auto-registration” mode, where it accepts and register automatically the first three keys used to start the engine after installing the immobilizer. So if the immobilizer was new, you should be able to start the engine with the existing keys.

    If all that fails, then there could be a problem with the wiring or the ECM.

    I am assuming things here. It might help to know what happened to the car before all this. I mean, why the immobilizer was replaced in first place. Did it stop starting out of the blue or were the keys lost?

  • shaun says:

    immo had water damage on these components tms3705bg4 , the oscillator next to it and on 11910 also c31 was broken off and missing a pad. the dealership told us to do 4-13 to handshake the ecu to the ecm. so you think the damage may have went to the ecm as well?
    i ordered a 2.0.4 mini vci cable. i will let you know what the results are later today. this is the first place on the internet that gave any response . thanks

  • zilog357 says:

    The ECM may have problems too, but in my experience, when the immobox is damaged, most of the times it is just that. Then jumping pins 4 and 13 will synchronize the data in the ECM with the immobox (Transponder ECU).

    In some models, the security light will flash steadily when it is expecting keys to be registered and won’t go off immediately in most cases unless at least three keys are registered. That is, starting the engine with each one of the keys. If the three keys are not registered, the lamp will go off eventually when the auto-registration cycle closes but may take one or two days.

    Also, watch the flash sequence just in case it is flashing a code. Sometimes it flashes a 2-digit code with pauses between the digits.

    The immobilizer system in those models is composed of (1) the engine ECM, (2) the immobilizer ECU, (3) the ring antenna with the amplifier in the ignition lock, (4) the keys and wiring. So if the problem persists, I would first check the wiring. I am not sure if you have the wiring diagram of that model, but if not, I am including it here.

    2013 Toyota Rav4 Engine wiring diagram

    2013 Toyota Rav4 Immobilizer wiring diagram

  • shaun says: data sheet to the tms3705bg4 i realized just now that that chip could have broken the antenna or amplifier when it shorted out.i will find out later today if that is the case.

  • zilog357 says:

    Check the diagrams I sent you in the previous message to see the connection and open both the immobox (or use the damaged one for reference) and the antenna amplifier to see if there is a direct connection, as I am not sure if the data is coupled by resistors. If it is, then there is little possibility that the short had broken the amplifier. If data is fed directly, then you may be right.

    Since there was water damage, consider the possibility of water damage in any other area or wiring that could be affecting the immobilizer.

    Just throwing darts in the dark because of course, I am in front of the vehicle and the problem is not a common one.

  • shaun says:

    i have a mini vci 2.0.4 . does one of these read the k and L lines? i can’t read most of the systems in the rav 4

  • shaun says:

    i hate to ask . do you have the schematic for the obd2 connector?

  • zilog357 says:

    Yes. It is called the Datalink and you will find it at the left in page one of the diagram in the link below.

    2013 Toyota Rav4 Datalink connector Diagram


  • Amy Culver says:

    Hello, I hope with your knowledge, you will be able to steer me in the right direction.
    I have a 05 corolla xrs 6sd that was given to me without any keys. Before it was given to me the person before me had removed the original steering wheel column and replaced with a new one. Problem is, someone stole the key that went to the new ignition.
    So my question is, before I spend money on doing what I hope will work. What are my options and will any of the answers you’ve given work for my scenario.

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