Here's what you should try, in order:
1. Check the Key: This is the most common cause.
* Try all your keys: Make sure you're using the correct key and that it's not damaged or worn.
* Check the battery in the key (if applicable): Some Cavalier keys have batteries for remote functions. A dead battery might prevent the car from recognizing the key.
* Have the key reprogrammed (if necessary): If you've recently had any work done on the car's electrical system, the key may need to be reprogrammed. A locksmith or dealership can usually do this.
2. Check the Car Battery: A weak or dying car battery can sometimes trigger the anti-theft system. Have the battery tested.
3. Check the Vehicle's Computer: A fault in the car's computer system can activate the anti-theft system. This often requires a diagnostic scan using an OBD-II scanner. An auto parts store can often perform a free scan.
4. Check the Immobilizer System: The immobilizer prevents the car from starting if it doesn't recognize the key. Problems with the immobilizer system often require professional diagnosis and repair.
5. Professional Help: If none of the above steps work, you'll likely need to take your car to a qualified mechanic or a dealership. They have the diagnostic tools to pinpoint the exact issue and repair it.
Important Note: Avoid attempting to bypass the anti-theft system yourself. This can be dangerous and could further damage your vehicle's electrical system. Always seek professional help if you're unsure about what to do.
