Skip the auto shop - Our mechanics make house calls

Q: Anti-theft system issues after leaving key in overnight. Car won't start.

asked by on

2006 Buick Lucerne won't start. Keys were left in over night. Has gas and battery is fine all lights come on. Security light Flashes for 10 seconds then shuts off. Horn won't work neither will the panic button so I'm assuming it's the anti-theft system.

My car has 40000 miles.
My car has an automatic transmission.

Hello. From what you describe it would appear that your security system may be activated and needs to be reset. This likely happened as a result of leaving the keys in the vehicle overnight. The procedure for resetting the security system is as follows. If this procedure does not reset the system then it may be possible that the system will need to be reset by a GM factory scan tool, requiring a visit to the dealership.

Reset procedure for GM Passkey III Security Systems:

  1. Insert the master key with the black head into the ignition lock cylinder

  2. Turn the key to ON but do not start the engine. The SECURITY light will turn on and stay on.

  3. Wait 10 minutes or until the SECURITY light to turn off.

  4. Turn the key to OFF for 5 seconds.

  5. Turn the key to ON but do not start the engine. The SECURITY light will turn on and stay on.

  6. Wait 10 minutes or until the SECURITY light to turn off.

  7. Turn the key to OFF for 5 seconds.

  8. Turn the key to ON but do not start the engine. The SECURITY light will turn on and stay on.

  9. Wait 10 minutes or until the SECURITY light to turn off.

  10. Turn the key to OFF. The key transponder will be learned on the next start cycle.

  11. Start the vehicle. If it starts and runs normally, the relearn is complete. If you need to program additional keys,

  12. Turn the key to OFF.

  13. Insert the next key. Turn it to ON within 10 seconds of removing the previously used key.

  14. Wait for the SECURITY light to turn off. That may happen quickly. You may not even notice it.

  15. Repeat steps 12 through 14 for all additional keys.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  • Home
  • Questions
  • Anti-theft system issues after leaving key in overnight. Car won't start.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The light next to the "drive" indicator has started flashing.

The flashing light indicates a fault with the transmission, in a similar manner the check engine light indicates a faulty sensor,etc. The best thing to do before spending money, is to spend money on a proper diagnosis as to why...

Q: Key on, no start and no dash lights. 1996 Ford Explorer

Hello. This is likely a loose terminal or corroded battery connection. Make sure the cables and terminals are clean. Also check the ground in the engine compartment. It sounds simple, but something like this can easily cut all power to...

Q: Air conditioner condensor bad 1995 Buick Park Avenue

Hi - if your air conditioner condenser (or compressor) have failed, you can continue to use the standard serpentine belt as long as the compressor is not engaged. This can be accomplished most simply by unplugging the wire going to...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...