Instead of using a lock cylinder to control ignition switch access, the Certification ECU controls Power Source ECU access. The Certification ECU verifies the Smart Key’s Vehicle ID and Key ID, and then the Certification ECU and Transponder ECU compare S codes. If they match, the Transponder ECU tells the Power Source Control ECU to allow ACC, ON, or START positions. It’s important to know that even if the Power Source ECU is “hot wired”, the car still cannot be started. The Immobiliser still must be satisfied in order for the car to Ready.