Engine Start-Up

This is an open loop mode. When starter is engaged, PCM receives input from battery voltage, starter relay, CKP sensor, CMP sensor, ECT sensor, IAT sensor, MAP sensor and TP sensor. Based on these inputs, voltage is applied to fuel injectors with PCM controlling injection sequence, rate, and pulse width. PCM provides ground for injectors to fire in proper order.

PCM determines proper ignition timing according to input received from CKP sensor. If PCM does not receive CKP sensor signal within 3 seconds after engine begins cranking, fuel injection system is shut down and a Diagnostic Trouble Code (DTC) is set in PCM memory.