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How to Reset the Passlock System on GM Cars

by Herman Cruz

A wide variety of GM cars come with a passlock theft system feature that is meant to keep GM cars from being stolen. However, it isn't uncommon for GM car owners to experience glitches with their passlock system when trying to start their vehicle. When this occurs, you will see the security (Theft Sys) light being displayed randomly, plus you won't be able to start your vehicle. To cope with this pesky glitch you can reset the passlock system when starting your car.

Insert your key in the starter, start you car as you usually would and let it stall. Keep the key in the "On" position. In other words, don't turn the key back to the "Off" position. You will know the key is in the "On" position because you can use the A/C, radio and see all the lights on the dashboard when it is in the "On" position.

Wait until the "Theft Sys" light on your dashboard stays on without blinking. This will take approximately 10 to 15 minutes.

Start the car immediately once the "Theft Sys" light stays on steadily. Remember to not turn the key off. Your car will now reset the passlock system and start as usual.


  • If your passlock system keeps giving your problems, it may be broken and you will need to take it to the dealership.
  • You can also have a mechanic disable the passlock system to prevent from being stranded in future occasions.

About the Author

Based in Orange County, Calif., Herman Cruz has been writing since 2007. His articles have been published in various content platforms and he also has written for Internet entrepreneurs who need assistance with writing sales letters and articles for their businesses. Cruz is pursuing his Bachelor of Arts in integrated composition, improvisation and technology at the University of California in Irvine.

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