Security light flashing and car won't turn over
Weak battery,or jumping some one can cause this,you will ahve to remove key from igintion,then remove positive cable from battery for about ten minutes,then place key in car and turn to the on position,then replace the positive battery cable,should reset the antitheft,if not you may need a lock smith or dealer to clear it.
chances are the pass lock sensor is defective the lock cylinder is the sensor and has two small thin wires coming out of the back of it those wires are probably broken have the lock cylder replaced and coded dont replace the key unless it is worn out and you need to figure out which key it is as there was 15 different chip resistors for this system
I have the exact same problem with my 1997 Chevy Malibu Base. I am puzzled, because it doesn't even have a key fob or security system... Normally I have to wait about 10 to 15 minutes before the light stops blinking. (Very frustrating)
you do have a security system it is less obvious though you need a new pass lock sensor as well, it is a different system though
I had that problem in my 2005 Monte Carlo & I brought a new battery & it started right up
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