Starter Circuit

When the ignition switch is turned to the RUN, BULB TEST or START position, battery voltage is applied to one side of the crank relay in the underhood accessory wiring junction block through circuit 3, the PCM-BCM Fuse in the fuse block, and circuit 439. When the ignition switch is turned to the START position, voltage is fed to through circuit 5, the CRANK SIGNAL Fuse in the fuse block, and circuit 806 through the underhood accessory wiring junction block to the PCM connector C2 terminal 23. Power is always provided from the CRANK MaxiFuse(R) in the underhood accessory wiring junction block to the common side of the crank relay contacts. When the PCM sees the crank signal and determines that conditions are OK for a crank, it supplies ground through circuit 625 to the crank relay. The crank relay now has both power and ground, to the relay coil, causing the relay to pull in. When this happens, and the gear selector is in either PARK or NEUTRAL, the power at the relay common contact is passed through circuit 1737, the transaxle range switch and circuit 6 to the terminal S on the starter solenoid. When voltage is applied to the starter solenoid terminal S, both solenoid windings are energized. The circuit through the pull-in winding is completed to ground through the starter motor. The windings work together magnetically to pull in and hold in the plunger, which moves the shift lever. This action causes the starter drive assembly to rotate as it engages with the flywheel ring gear on the engine. At the same time, the plunger closes the solenoid switch contacts in the starter solenoid. Full battery voltage is applied directly to the starter motor, which cranks the engine.

When the solenoid switch contacts close, voltage is no longer applied through the pull-in winding, as battery voltage is applied to both ends of the windings. The hold-in winding remains energized, and its magnetic field is strong enough to hold the plunger, shift lever, drive assembly and solenoid switch contacts in place to continue cranking the engine. When the ignition switch is released from the START position, battery voltage is removed from circuit 5, the CRANK SIGNAL Fuse, and from circuit 806 to connector C2 terminal 23 of the powertrain control module. The PCM then removes the ground from circuit 625 to the crank relay. This causes the crank relay to release, opening up the relay normally open contacts. This removes the power from circuit 6 to the terminal S of the starter solenoid and the junction of the two windings. Voltage is applied from the motor contacts through both windings to ground at the end of the hold-in winding. However, the voltage applied to the pull-in winding opposes the voltage which was applied when the winding was first energized. The magnetic fields of the pull-in and hold-in windings now oppose one another. The return spring causes the drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.