GM Service Manual Online
For 1990-2009 cars only

Cranking Circuit

The cranking circuit consists of the following components:

    • The battery
    • The starter motor
    • The ignition switch
    • The park/neutral switch
    • The powertrain control module (PCM)
    • The starter motor relay
    • All related electrical wiring

For detailed schematics of the starting system, refer to Starting and Charging Schematics .

Starter Motor

PG-260 Starter Motor


Object Number: 101080  Size: SH

The PG-260 achieves gear reduction at a ratio of 5:1 through planetary gears. The motor's relatively small size and light weight offers improved starting performance and reduced current requirements for larger gasoline engines. Do not overhaul the PG-260, it is serviced by replacement only.

The PG-260 has the shift lever mechanism and the solenoid plunger enclosed in the drive housing in order to protect them from exposure to dirt, icing conditions, and splash.

The solenoid windings energize when the ignition switch is in the START position. The resulting plunger and the shift lever movement causes the pinion to mesh with the engine flywheel ring gear, the solenoid main contacts close, and engine cranking takes place. When the engine starts, the pinion overrunning clutch protects the armature from excessive speed until the ignition switch is released, at which time the plunger return spring causes the pinion to disengage. In order to prevent excessive overrunning, release the ignition switch immediately when the engine starts.