Q: Car won't start after repair work

Hello there. If the engine is cranking and not starting, and the security light is on, then the security system may be having problems. This does not necessarily mean that he caused this. Most of the time, this is caused by a failing pass-lock sensor in the key lock cylinder. These will fail for no reason. In some cases, resetting the system will work, but most of the time the sensor needs to be replaced. This is part of the key lock cylinder. A mechanic would use a scan tool to see if the computer is picking up the key when it is installed. If not, then they would try another key, which would help to determine if it is the sensor. If you need further assistance, I recommend you have a mechanic, like one from YourMechanic, inspect for possible electrical problems and inspect for any faults retrieved by the computer.