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Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 24204
Experience:  14 years GM dealer Technician.
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I changed my key key cylinder, pcm,bcm,security light went

Customer Question

I changed my key key cylinder, pcm,bcm,security light went off,still will start for a second and die. I put my pcm from my 1996 gmc jimmy in my blazer and will run don't no
JA: The mechanics have tons of experience in that area. Are those all of the "symptoms"?
Customer: My battery will drain while running with the gmc pcm
JA: Anything else I can tell the Chevy Mechanic before I connect you two?
Customer: No
JA: Got it. Let's get this figured out. I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the Chevy Mechanic about your situation and connect you two. You'll be on the road in no time.
Submitted: 6 months ago.
Category: Chevy
Expert:  Pete replied 6 months ago.
My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here. If you did not have the PCM programmed this can cause this here.The BCM also has to be replaced with a new one as a used one is already programmed and locked to a different vehicle and cannot be unlocked for your model here.It will need programmed as well and both of these are programmed at a GM dealer.They will usually charge an hours labor and the computers need to be in the vehicle with the vehicle at the dealer in order for them to do this.If this was already done let me know. If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete
Customer: replied 6 months ago.
I have got the key , ignition, pcm,bcm,all out of the same vehicle, so everything matches .i shouldn't need to program it should I. Would it matter if stock stereo is not in the truck.i do not have that anymore.if so can I bypass that
Expert:  Pete replied 6 months ago.
If it was removed from another like vehicle even if it is the same exact vehicle yes it still has to be programmed.It programs to your vehicles VIN and a used BCM cannot be used on a different VIN vehicle.Once the BCM is programmed to a certain VIN it locks to that VIN and if you plug it into your vehicle it will not allow the engine to start.A new one has to be obtained and programmed to your model in order to work.It doesnt matter if the stereo is in or not for this issue here.The PCM can be reprogrammed from a different VIN to yours but not the BCM. Let me know if you need anything else and feel free to rate my help here. Thanks Pete