Starting System: Description and Operation

Starting System

The starting system consists of the:

- starter motor.
- ignition switch.
- digital Transmission Range (TR) sensor.
- mini ISO relay.


Starting System - Starter Motor

The starter motor:

- is a permanent-magnet, gear reduction, 12V DC motor.
- has an integral starter solenoid.


Starting System - Starter Relay

The starter relay:

- is a mini ISO relay.
- switches power to the starter solenoid to engage the starter motor when it receives a START signal from the ignition switch.


Starting System - Normal Operation

When the starter solenoid is energized, a magnetic field is created in the starter solenoid windings. The iron plunger core is drawn into the starter solenoid coil, and a drive lever and pin connected to the starter drive engages the drive pinion gear to the flywheel ring gear. When the plunger is pulled all the way in, its contact disc closes the circuit between the battery and the motor feed terminals. This sends current to the motor, and the drive pinion gear cranks the flexplate to start the engine. When current flows to the starter motor, the starter solenoid pull-in coil is bypassed, and the hold-in coil keeps the drive pinion gear engaged with the flywheel.

The starting system uses a digital TR sensor that recognizes the vehicle is in either PARK or NEUTRAL and the ignition switch is placed in the START position. It sends a signal to the mini ISO relay that, in turn, sends a voltage signal to the starter solenoid, which will engage the starter motor to crank the engine at a speed fast enough to permit the engine to start.