Cadillac 2005 SRX Owner's Manual page 70

Your vehicle has an Immobilizer Vehicle Theft-Deterrent
System. The key has a transponder in the key head
that matches a decoder in the vehicle's steering column.
2-4
One key works all of
the lock cylinders on
the vehicle.
If a replacement key or any additional key is needed,
you must purchase it from your dealer. The key will have
PK3+ stamped on it. Keep the bar code tag that came
with the original keys. Give this tag to your dealer if
you need a new key made. For more information
on Immobilizer see Immobilizer Operation on page 2-19.
Notice: If you ever lock your keys in your vehicle,
you may have to damage the vehicle to get in.
Be sure you have spare keys.
In an emergency, contact Cadillac Roadside Assistance.
See Roadside Service on page 7-6.
If your vehicle is equipped with the OnStar system with
an active subscription and you lock your keys inside
the vehicle, OnStar may be able to send a command to
unlock your vehicle. See OnStar
for more information.
®
System on page 2-40