Starting System: Description and Operation

STARTING SYSTEM

The starting system consists of the:
- starter motor.
- starter switch, part of the ignition switch.
- digital transmission range (TR) sensor (automatic transmission-equipped vehicles).
- starter motor solenoid relay switch.
- starter solenoid.
- starter drive.

The starter motor:
- is a permanent magnet, gear reduction, 12 V DC motor.
- has an integral starter solenoid.
- has an over-running clutch in the starter drive.
- is serviced as an assembly.

The starter motor solenoid relay switch:
- controls current to the starter solenoid.
- is engaged by the ignition switch.
- connects the battery to the starter motor.

The digital TR sensor on automatic transmission-equipped vehicles prevents starter motor engagement unless the transmission is in the NEUTRAL or PARK position.

The starter drive:
- is operated by the starter solenoid.
- engages the flywheel to turn the engine.
- has an internal over-running clutch to disengage the starter motor when the engine starts.

The starter solenoid:
- is an electromagnet.
- engages the starter drive to the flywheel.
- when energized, the contacts close, connecting the battery to the starter motor. This causes the starter motor to turn the starter drive.
- is kept in the energized condition by a hold-in winding until the starter switch is released.

When the ignition switch is turned to the START position, the starter motor solenoid relay switch is energized, connecting the battery to the starter solenoid. The starter solenoid moves the drive lever and pin to engage the starter drive with the flywheel ring gear and connects the battery to the starter motor.