Lost key

2005 BUICK LA CROSSE
110,000 MILES • V6 • AUTOMATIC
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ANTHONY.
  • MEMBER
  • 2 POSTS
I've lost my key. Can I just replace the ignition switch or do I have to replace the key cylinder?
Mar 20, 2019 at 7:50 PM
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SCGRANTURISMO
  • ASE Certified Mechanic
  • 4,897 POSTS
  • ASE Certified Mechanic
Hello,

You will have to have another key cut either at the dealership or at a locksmith shop. The reason why, is that your vehicle uses a chipped key to start it. I believe that General Motors uses resistance in the circuit to get to a final voltage, and if the Power-train Control Module (PCM) does not receive that exact voltage your vehicle will not start.

Thanks,
Alex
2CarPros
Mar 20, 2019 at 8:06 PM
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ANTHONY.
  • MEMBER
  • 2 POSTS
Thank you.
Mar 21, 2019 at 7:11 AM
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STRAILER
  • ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Hello

Here are diagrams and instructions to check the ignition key lock tumbler. Get the new unit from the dealer and bring your VIN and proof of ownership and they will code the key for you. Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.
Mar 23, 2019 at 4:28 PM
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