Vehicles With Key Transponder Module (KTM)

Engine cranking is controlled by ignition switch, ECM, Body Processor Module (BPM), Key Transponder Module (KTM), ignition key reader exciter, ignition key transponder, park/neutral switch, and not-in-park switch at gear selector. KTM receives signal from ignition switch as key is turned to ON position (II). KTM energizes reader/exciter and key transponder broadcasts security code.

If code matches KTM code, KTM outputs an okay to start signal to ECM. ECM enables fuel and ignition. ECM outputs security signal to BCM. BCM receives park signal from not-in-park switch at gear selector and enables cranking if security system has been disarmed. With ignition switch in START position (III), crank signal is received by BCM. BCM grounds starter relay coil to energize starter. ECM receives starter relay coil signal and sets engine starting values.