Description & Operation
When ignition switch is turned to START position, battery voltage is applied to coil-side of crank relay and to Powertrain Control Module (PCM) crank signal input. PCM verifies through Body Control Module (BCM) that PASSLOCK(R) theft deterrent system has enabled engine to start. PCM then grounds control circuit of crank relay. When crank relay is energized, it allows voltage to starter solenoid "S" terminal.
When voltage is applied to solenoid windings, this creates movement of solenoid plunger and shift lever, causing drive pinion to engage flywheel and close solenoid switch contacts. See Fig 1 . When solenoid switch contacts close, starter motor energizes and cranks engine. As engine starts, pinion overrun clutch protects armature from excessive speed until ignition switch is opened and plunger return spring disengages pinion.