Theft Systems : Theft systems are designed by the vehicle manufacturer as a factory theft alarm system. These systems may include a factory intrusion system, door ajar monitoring, ignition system monitoring, starting enabling/ disenabling, fuel and ignition system enabling / disenabling and a horn or siren. Some theft systems read a chip key, transponder remote or the actual lock on the vehicle. Theft systems can be hard to diagnose and repair without factory equipment since many vehicles with factory theft systems require factory equipment to read codes, read data and program the system. Theft systems will indicate a problem usually with a theft system light which is vehicle specific. An automobile owner may notice a problem if the vehicle alarm goes off for no reason, alarm will not disarm, vehicle will not start and theft lamp is illuminated or flashing and or remote transponder is unable to arm or disarm the alarm.