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Volkswagen Jetta Security System

1996 VW Jetta. Recently the electric door locks are unlocking while I am away. I have tried to lock them manualy and also using the electric button. However when I return to the car it is completely unlock. Does anyone have a suggestion?


  • Not a mechanic but it sounds mechanical. As if there is a problem in the wiring or something. I would take it to a VW dealer and have them look at it.
  • HELP!!! How do you deactivate a 96 jetta volkswagen. I can't start the car. This is a brought used vehicle which I didn't know had an alarm. I think I made a mistake and activated it through the ignition alarm when I parked and shut off the engine. It seems like it has a duel alarm. I can deactivate the alarm by locking the doors and unlocking with the key. However, when I tried to start the engine it won't start. I don't see any switch that is related to the alarm to deactivate.
  • I bought a 2005 1/2 (newer model) Jetta about a month ago and just within the past week it decideds it wont chirp after I lock it. So I dont know if this means its not setting the alarm or what. I hit the lock button twice and normally it chirps to let me know its armed, but i doesnt. Any ideas on whats going on?
  • bpeeblesbpeebles Posts: 4,085
    The alarm will not "arm" unless it senses ALL the doors/trunk/hatch/hood as being closed. Your problem is likely a sensor on one of these.

    Also, I thought that pressing the button on the keyfob ONCE sets the alarm... has VW changed the way the keyfobs work?

    The only double-click on my keyfob is to UNlock all doors. (otherwise only drivers door unlocks)
  • jeffyscottjeffyscott Posts: 3,855
    Also, I thought that pressing the button on the keyfob ONCE sets the alarm... has VW changed the way the keyfobs work?

    I don't think it has changed, we lock all doors with one press on our 2005.5 and there is a little chirp. I assume that when all doors are locked the alarm is that correct? Alarms are not something we would ever worry about, those things are just an annoyance as far as I am concerned, we just want the doors locked.
  • bpeeblesbpeebles Posts: 4,085
    I assume that when all doors are locked the alarm is that correct?

    Actually - I beleive that all the doors can lock and the alarm may NOT be set.

    The way to KNOW that the alarm is "armed" is to see the blinking indicator on the top of the drivers door. (The A4 vehicles have the indicator there... your A5 may have it in differnt location.)
  • jeffyscottjeffyscott Posts: 3,855
    Perhaps that is a programmable option :confuse: . The red light does blink on ours after locking with one press on the remote.

    I checked and our manual says:

    "Activating the alarm system - Lock the vehicle"
  • bpeeblesbpeebles Posts: 4,085
    Yes it is "programmable" option. Anyone with a VagCom can change it for you.
  • how do you bypass the anti theft system so it will shut it off and i can start my car.please help me
  • Recently bought a 2000 Jetta TDI. Installed new battery thing morning due to the fact that the car had been sitting for several months wihout one in it. Engine spins over fine and starts for about 2 seconds, then promptly dies as if you cut the engine off yourself. There is a light flashing on the dash that looks like the outline of the car with a key in the middle of it...I'm guessing it is a security system light. Any ideas on how to reset the security system? I also need ot know how to get the security code for the radio...Thanks for any input you may have.
  • bpeeblesbpeebles Posts: 4,085
    A dead battery in any modern vehicle is bad news. (as you have discovered)

    If you are lucky, a previous owner has written the battery code in the ownersmanual. If not, then you need to pull the radio and get the serial # from it.... and VW dealership can decipher the code from that.


    Now - as for starting and immediatly quitting. You are correct in assuming that it is the "immobilizer" which behaves like that. This is NORMAL for the immobolizer to 'forget' the SKC (Secret key Code) if the vehicle is not started for several months.

    The security system on VW is based on the Mercades-Benz design which is nearly impossible to bypass. (You car cannot be stolen by starting the engine!) You MUST use a key which is both cut correctly for the keyhole and satisfies the immobilizer built into the dashboard electonics. (simply cutting a key to fit is not good enough)

    Some people with your problem have reported that they left the key in the ignition with ignition on for about 10 minutes.... and the immobilizer light was now extenguished. They could then start the engine.

    Others have reported that the computer needed to be "rebooted". I am not sure what that means

    There is a very slight possibility that the reciever (ring around the ignition key-hole) is defective.... but that is the best advice I can give you.

    There is a way to temporarrly "bypass" the immobilizer. There is a step-by-step procedure which involves using the tripmeter to input a secret code into the computer. The secret code is provided by a VW dealership with the following prerequsets;
    *)Customer must provide proof of authorized vehicle operation/ownership with vehicle documents and identification.
    *)Key tag with covered secret number is available.
    *)Mechanically correct key available.

    Perhaps your problem with starting and staying running is NOT the immobilizer at all. Perhaps you need to check for airleaks in the fuel system. Sitting unused for several months may have dried out the seals in the injector pump so it is sucking air.
  • I am in the middle of a 2,500 mile road trip and today while on the freeway heard and felt a huge bang or knock on the drivers side of the car, then noticed when I pulled over that the MIL (malfunction indicator light) was on. I understand this relates to the car emissions system - is it something I should have fixed immediately, or can I complete my trip without damaging the car and take it to a reputable repair shop where I live?
  • patpat Posts: 10,421
    Your other post is better placed - let's ask anyone who can help to respond at this link: mexjetta2000, "Volkswagen Jetta Maintenance and Repair" #5517, 30 Dec 2007 5:26 pm. You also may want to click on the new Answers System feature linked at the top of the page and ask there.

    Good luck!
  • I have a 2000 Jetta and the deactivating sensor for the security in the door lock seems to be bad. When locking or unlocking with the key, the security turns on but rarely turns back off, causing the horn to honk for 30 seconds or so when I start the car. The Keyless is not working either, I replaced the batteries in the key fob but that wasn't it.

    I'm wondering, to avoid paying for a new lock sensor, is there a way I can just disable the alarm? I've heard that the alarm unit is behind the light switch in the dash.
  • bpeeblesbpeebles Posts: 4,085
    In your 2000 Jetta (MK IV), the doors have several micro-switches in them which detect various things like "door open/closed, locked/unlocked...etc". These switches can go bad and send unexpected signals to the security system. (like the door is locked and unlocked at the same time!)

    One can often detect which door has the troublesome switch with a VagCom. Unfortunatly, to get at the switches, the entire guts of the door need to be taken apart.

    I realize this does not answer your question... but thought you may wish to know more about the problem you are encountering.
  • I've got an idea of how to get my problem solved, I just want the alarm to never go on in the first place. To clarify my problem, I need to be able to lock the doors...but the key fob is not working and I'm not intrested in paying that kind of money to fix. When I lock with the key, the alarm always works and arms the car, however when I unlock the car with the key, it almost never disarms causing the alarm to go off when the car is started or other doors are opened.

    The disarm in the trunk works. If I use the key back there to open the trunk it will disarm the alarm, then I take the trunk closed sensor away from the trunk and leave it open, the security should never arm again because it will always think the trunk is open. Is there any reason that wouldn't work?
  • bpeeblesbpeebles Posts: 4,085
    Dont forget there is also a "Hood Opened" sensor too.

    Also, beware that if you do try to "fool" the security system in the way you are describing, you may end up with a perminant "door opened" indicator on the dashboard.

    Be VERY careful that you do not mess with the "immobilizer" circuits. The alarm may be annoying... but the "immobolizer" will simply kill the engine and you will be stranded. The alarm and the immobilizer are both part of the security system and they may be tied together in some ways.

    If you really are considering messin with trying to "bypass" the alarm... why not go ahead and just fix the microswitches in the door and be done with it?

    There are several step-by-step procedures on the internet showing how to replace the door switch microswitchsx ($3 with Radio Shack part)

    Removing door panel

    Removing front door parts (from thread above)
  • bpeebles,
    Thanks for the advice about the imobilizer. I tried my idea last night with the hood actually. It seemed to work for about 5 min, so I buttoned up the door rag and 2 min later I went to move the car and it armed again.

    I read the switch replacement post, but as with the hood sensor, I find myself asking... if there's just one plug that gets both the open and closed signal, why don't I just unplug it and disarm with the trunk to never have to mess with this thing again. It sounds like a major PITA to get the door pannel off, then get the lock assembly drilled out from the rivvets, dremmel tools....I just hate security and if I can get it to never come on, I'd be happier.

    Also, if I were to know where the keyless entry module is for the car, and it's not a $500 part, I MIGHT be interested in replacing that as it's probably not ordeal this is and I'd get my keyless and security problem fixed as I'd be able to dissarm with the keyless.

    I've asked around and gotten 3 different answsers on this, where is the alarm horn on this car? Its a 2000 Jetta base model, a GL I believe. If I were to just unplug the horn and ignore the alarm altogether, would that trigger the imobilzer? I've heard that 2000's don't have an imboilizer, is that true, and is there a way I can verify that on my car?

    Thanks to everyone for the advice!
  • bpeeblesbpeebles Posts: 4,085
    I understand that the antenna for the remote is behind the dashboard. It follows that the reciever circuit must be nearby.

    I beleive the "alarm horn" is one-in-the-same as the normal horn.

    Not certain about the 2000, but my daughters 2001 DEFINATELY has an immobelizer. She has complained about the engine starting and the immedeatly shutting down. (this is how the immobelizer works)

    When I hooked up my VagCom and ran diagnostics... the onboard computer reported that the immobelizer had been "triggered" reciently.
  • I have a 2000 jetta gls and I went out the other day to start it up and the dorr lock were locking the door continually. I had to disconnect the battery. any thought
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