New ignition key lock and truck won't learn new switch

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Detector, Dec 23, 2012.

  1. Detector

    Detector New Member

    The ignition switch(key switch) on my 2007 Silverado had been giving me trouble and not wanting the let me turn the key. I bought a new key lock and installed it today and attempted to do the "learn new key" process, but it doesn't seem to be working. I followed these steps.

    1. Turn key to ON and try to start truck then let it go back to ON and leave sit foapproximatelyly 10-15 minutes and the Service Theft Deterrent System will go out. It never does.
    2. Turn ignition off wait 5 seconds, and repeat step 1. two more times.

    One thing I see is the Service Theft Deterrent System light never does go off like I've seen posted. What might I be doing wrong? I have a brand new lock and key installed.

  2. j cat

    j cat Epic Member 5+ Years 1000 Posts

    I do not have an answer to your question with this new issue you have.

    with the original problem the key lock cylinder would not work , did you get a new key made from the dealership first before replacing the lock cylinder.

    2007 I would say the key, not the lock cylinder was the problem . having a backup key never used is a good bit of insurance.

    however using a worn key will in a short time chew up the lock cylinder.
  3. Detector

    Detector New Member

    I have a spare key and it doesn't work either. With the old cylinder and keys the ignition won't turn at all. With the new cylinder and keys it works as it should other than no start.

    I did find 2 work-arounds.

    I can use the remote starter to start it then use the new key or If I take the old key and hold it next to the new key as I start it it will work.

    Last edited: Dec 23, 2012
  4. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    I've had new keys made for my original cylinder ('09 Av), followed the steps in the OM and it worked (did this twice).

    Sounds like the new cylinder might be the problem, did you buy it from a dealer?
  5. j cat

    j cat Epic Member 5+ Years 1000 Posts

    would have the automotive locksmith do a security bypass. this should stop any of these issues.

    not being that old a vehicle surpised the cylinder locked up. usually the worn key is the problem.
  6. Jamm3r

    Jamm3r Member 2 Years 100 Posts

    Be sure your new key has a working transponder. Perhaps it doesn't work in which case you can try another key -- you had at least two made, right?

    Usually the procedure is to start with a working key rather than wait for a 10 minute timeout... never tried that... if you still have your old key you might be able to hold it in place next to the cylinder and fool the computer into thinking that's the one you're using and then be able to follow the regular programming procedure.
  7. redvett

    redvett Rockstar 100 Posts

    Try the relearn.

    In this system, the vehicle theft deterrent functions are provided by the theft deterrent control module. There is a transponder embedded in the head of the key that becomes energized by the exciter coils in the ignition lock cylinder when the ignition switch is turned on. The energized transponder now transmits a signal containing a unique value to the theft deterrent control module. If the module accepts this value, then there is an additional communication that takes place between the module and the key. If the module and the key agree, then the module sends the fuel enable password to the PCM. If the PCM recognizes the password, then the vehicle starts and runs normally. If any of the communication between the module and the key is incorrect or the PCM does not recognize the password, then the fuel injectors are disabled. The ignition key is a normal looking key with no visible contacts as in the Passkey or VATS systems. The transponder is located in the key head. The transponder value is fixed and cannot be changed. These keys are usually identified by the letters PK3, or PK3+ stamped into the steel body. A relearn will be necessary if any of the following have been replaced: any key, the theft deterrent control module or the powertrain control module (PCM). When the theft control module is being replaced, the module will learn the existing keys immediately. However, the PCM must learn the new fuel enable password from the new module. If you are replacing a PCM with a PCM that has been used in another vehicle or has been remanufactured, then a relearn must be performed in order for the PCM to learn the fuel enable password. Keep in mind that when you perform a relearn on this system, all previously learned keys will be erased from the theft deterrent control module’s memory. Any additional keys may be relearned immediately after the first relearn has been performed by inserting the additional key and turning the ignition switch to the “On” position within ten seconds of removing the previously learned key.

    In order to initiate the relearn process:

    1. Insert a master key (black head) into the ignition switch.
    2. Turn to the “On” position without starting the engine. The security light should illuminate and stay on.
    3. Wait approximately 10 minutes or until the security light turns off.
    4. Turn off the ignition switch and wait 5 seconds.
    5. Repeat steps 2 through 4 two more times with the same key.
    6. Turn the ignition off. The vehicle will now learn the key transponder information on the next start cycle.
    7. Start the vehicle. If vehicle starts and runs normally, and security light is off, the relearn is complete.

    If additional keys are to be relearned:

    8. Turn the vehicle off.
    9. Insert the next key to be learned and turn the ignition switch to the “On” position within 10 seconds of removing the previously used key.
    10. Wait for the security light to turn off. It should happen quickly. You may not even notice the light come on, because it will learn the key transponder immediately.
    11. Repeat steps 8 through 10 for any additional keys.
  8. rsmits

    rsmits New Member

    What are you guys on about? My 2007 Silverado doesn't need a "master" key - just an ordinary key from the hardware store.
  9. redvett

    redvett Rockstar 100 Posts

  10. redvett

    redvett Rockstar 100 Posts

    GMT 800 1999 to 2007 used a sensor in the lock cylinder and NO chip in the key, GMT900 2007 and later used more advanced technology and a chip in the key for passlock.

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