* Faulty Key: The most common cause. The car's computer may not recognize the key's transponder chip. Try all your keys. If none work, the problem is almost certainly the key or the transponder. You'll need a new key programmed by a locksmith or dealer.
* Dead Battery: A weak or dead battery can prevent the car from starting and can also trigger anti-theft features. Try jump-starting the car.
* Faulty Immobilizer System: The Passlock system (GM's anti-theft) could have a malfunction. This might involve the receiver, the transponder chip in the key, or the car's computer itself. A scan tool capable of reading GM's system is needed to check for any codes relating to Passlock.
* Security System Issues (Aftermarket): If you have any aftermarket alarm or security system installed, it could be the culprit. Consult its manual to see how to disable it or reset any codes.
What to do:
1. Try all keys: This is the easiest and most common solution.
2. Jump start the car: A weak battery can mimic anti-theft issues.
3. Check the car's battery terminals: Ensure they are clean and tight. Corrosion can prevent proper electrical contact.
4. Have the car scanned: Take your Monte Carlo to a mechanic or auto parts store that can perform a diagnostic scan. This will check for any trouble codes, including those related to the Passlock system or other potential issues. This is crucial as it can pinpoint the real problem.
Important Note: There are no simple tricks or "secret" reset procedures for the 1997 Monte Carlo's anti-theft system that bypass security measures. Attempting to bypass the system could damage the car's computer. Always address the root cause of the starting problem, not just the symptom.
