Car immobilizer

A starter motor immobilizer is an effective (but not certain) means of protecting your car against theft. It has the drawback that a would-be thief will try to render it inoperative and in the process damages your car. The present circuit is a simple version of car immobilizer and tends to confuse the thief. This is because the car appears to function normally, but it does not start. Has it broken down or is there some sort of protection circuit active?