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My Car Won't Start & the Security Light Is On

by Robert Moore

The security light on your vehicle serves has two purposes. On some vehicles, it will flash when the ignition is off, and the OEM security is activated. Its other main purpose is to indicate that the security of your vehicle may have been compromised, and the engine has been immobilized to prevent potential theft. Don’t assume right away that it means someone tried to break into or steal your vehicle. In most cases, it means that there is a failure somewhere in the security system.

There is no quick bypass to get around the security system or immobilizer. OEM security systems with the ability to immobilize go back as early as the late 1980s, but programmable keys didn't become popular until the mid 1990s when manufacturers switched from OBD-I to OBD-II computer systems. Most new cars today have programmable keys and engine immobilizers.


  • Sometimes the failure is key related, so try your second key to see if that works. 
  • Sometimes it is just a matter of reprogramming the ignition key. In most cases this must be done by a dealer, but some models have an on-board programming feature.
  • Some locksmiths can program ignition keys and will often do it at a discounted rate compared to a dealership. 

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About the Author

Robert Moore started writing professionally in 2002. His career started has head writer and Web designer for VFW post 1224 in Hamburg, Michigan. He has prepared business plans, proposals and grant requests. Moore is a state of Michigan-certified mechanic and is pursuing an Associate of Arts in automotive technology from Lansing Community College.

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