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?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. 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: After tire rotation thumping noise developed - 2006 Chevrolet Avalanche 2500 Automatic

The "thumping" sound you mention seems more like the torque convertor lock-up clutch in the transmission failing. It tries to lock up, can't recycles, etc. GM has a service bulletin on this problem - TSB Reference #3438A. Discuss this with...

Q: Car won't start - 2002 Nissan Sentra

Hi there. It sounds like the starter is engaging, but not extending the armature to turn the engine. However, it may be due to faulty relay, wiring or other electrical issues. The best way to determine exactly what’s causing this...

Q: Q: Car is overheating

The flapping noise may have been the serpentine belt breaking. Once the belt broke completely both the water pump and alternator stopped turning, thus accounting for both the overheating the charging light coming on. In all probability you just need...

Related articles

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...