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Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
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1999 Chevy Lumina: 2 days ago the security light came on

Customer Question

I have a 1999 Chevy Lumina. 2 days ago the security light came on. It hasnt come back on since. What is the problem?
Submitted: 9 years ago.
Category: Chevy
Expert:  Bob replied 9 years ago.
Hello, The most common problem on these units with the security system is the wiring to the ignition lock cylinder breaking, or the cylinder itself going bad. But the problems are not limited to just those two items. If the car is working fine now, it may have been a minor glitch in the body control module that is no longer being a problem. If the car is still having the issue, the only way to test this particular system is with a class 2 scanner, like the dealers use. The dealer also has special equipment for reading the key resistance value and the VAT's interrogator in the car. This is a class 2 device that works through the body control module and many different sensors and that is the only tool that will interface with it for test purposes to retrieve any codes that may be stored in the memory of the body control module, which would point us in the direction of any failed sensors or other components. Even if the problem were the broken wires or a defective lock cylinder the system would need to be programed again after they were repaired. This would also need to be done with the special equipment. Many of the systems have relearn procedures that will clear the problem for a short time, but your system is not set up that way. Thanks