Starting System

The starting system controls the cranking of the engine. Under normal operation, when the ignition is turned to START, the PCM receives the following inputs:

• Request to crank engine message from the BCM
• PATS enable message from the BCM
• Park or neutral input from the automatic transmission

When the PCM receives the correct inputs, voltage and ground is supplied to the starter relay coil. When the starter relay coil is energized, it provides voltage to the starter solenoid, allowing the starter motor to crank the engine.

The PCM disengages the starter once an engine Revolutions Per Minute (RPM) threshold is reached, a set crank time is exceeded or the ignition is turned off.