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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29523
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2004 trailblazer: that is having issues with the security system

Customer Question


i have a 2004 trailblazer that is having issues with the security system. how can the security system be reset?
Submitted: 6 years ago.
Category: Chevy
Expert:  AutoTech36 replied 6 years ago.



May I ask what kind of a issue is happening? There really isn't anything to reset if there is a problem.


Auto Tech36

Customer: replied 6 years ago.
<p>when key is inserted and attempt is made to start the vehicle it does not start but the speedometer sporaidically jumps to 80 mpg or so. several light light up or flash.</p><p>it was taken to a shop a couple of weeks ago - when it was giving trouble but still starting - they said it was related to the security system.</p><p> i've read a few posts online that refer to using an ohm meter on the key but our keys do not have a chip in them.</p><p> </p>
Expert:  GM Tech (Cam) replied 6 years ago.
Welcome, and thanks for using Just Answer. I am Cam, and I will do my best to assist you. When you are finished please click on accept only if you are satisfied. I don't get paid unless you do.Please do not accept if you cannot leave positive feedback. I don't know if you are a tech or a just working on your own vehicle so we may have to fine tune the answer. I only know as much about your problem as you have told me in your post, so my answers will be based on what you tell me so please add all the details you can. About your vehicle,

You can try a relearn, but I suggest you bypass it.
Turn the key on, with the engine OFF.Try to start the engine, then release the key to ON, Engine will not start. Watch the security telltale, after about 10 mins, it will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes. You must turn the ignition OFF before attempting to start the vehicle.

Start the engine .

If that does not last, try this device to bypass it.
Customer: replied 6 years ago.

i've already tried the "10 minute plan" twice but I should tell you that the key does NOT have a chip in it. Am willing to give it a 3rd try (both tries were yesterday)... got that "suggestion" from an online search and from a guy at Advanced Auto Parts that had also had the same problem. Don't know if he had a chip in his key or not.


I presume the chip would matter. Does it or not? If not, there would be no need to try a third time. Since my first 2 times were yesterday should I start over today - keeping in mind my keys have no chips.


A friend suggested unplugging the computer to 30 minutes or so and plugging it back in. Do you think that could work? and if so, where is the computer located on a 2004 Trailblazer?


Just went to the website you suggested to check things out. Under the installation instructions they don't even list a chevy trailblazer - this concerns me. I have a disability and some positions would be hard for me to get into.


also, this website keeps asking for an email and password. when i put my password XXXXX it tells me it is wrong. i don't recall even seeing a place to register that information. can you tell me what to do about that as well. i'm not receiving any emails from this site but presume i should be since they ask for that info.


Expert:  GM Tech (Cam) replied 6 years ago.
Correct the chip is not this design, rather it has the sensor as part of the ignition cylinder and it measures the rotation.
I assure you that they do support the the trailblazer and is the 4th listing from the top. The BCM is at the rear seat so you will not need to be a contortionist to install it.
If you want to try that device, click the PRO VATS Full Bypass link on the left side of the page and half way down is the link to purchase. It does come with the 30 day money back guarantee.
Customer: replied 6 years ago.

what is a BCM? and do I understand correctly that the fact that my keys do not have a chip will not affect the "10 minute plan" and that I should try that again? if so, once more or 3 more times?


where is the computer located so that i can also try to disconnect it and reconnect it as well?


thanks so much for trying to help me out.

Expert:  GM Tech (Cam) replied 6 years ago.
Yes try the relearn again 3 times.
The BCM is the Body Control Module
Reconnecting it will not do anything but try resetting it.
Take the battery cables off the battery, hold the ends together for 10 seconds then attach them to the battery and see what happens. This will reset the whole vehicle.
Customer: replied 6 years ago.

thanks Cam - we will try that after while - may have to be tomorrow because we had to abandon the vehicle away from our home - may take until tomorrow to go back since it's getting dark now.


will let you know how it turns out.



Expert:  GM Tech (Cam) replied 6 years ago.
Bookmark this page so you can easily navigate back to it, and so you know, you can reply at any time for follow up information regarding this issue, even after you accept my answer and I will reply.

Customer: replied 6 years ago.



is the BCM the same thing as the computer that my friend suggested i try to unplug /replug? if not - where is the computer located so i can give that a whirl also when i go back to the vehicle?

Expert:  GM Tech (Cam) replied 6 years ago.
It is, this device is attached to the fuse block under the second row drivers seat but it is atached in a complex way, not a simply unplug, that is why I suggested the battery cable trick as it does the samething.