Starting System: Description and Operation

Starting System

The function of the starting system is to crank the engine fast enough to allow the engine to start. Heavy cables, connectors and switches are used in the system because of the large currents required.

The starting system consists of a pre-engaged type starter motor, battery, remote control switch (ignition switch) and relay. The operation of the starter relay is controlled by the powertrain control module (PCM).

To protect the starter motor from damage, the PCM prevents the starter from being engaged when the engine is running. This is done by the PCM inhibiting the starter relay operation.

Vehicles equipped with automatic transmission have a transmission range sensor attached to the circuit which prevents operation of the starter motor unless NEUTRAL or PARK are selected.

USA market vehicles equipped with manual transmission have a clutch pedal start inhibit switch which prevents operation of the starter motor unless the clutch pedal is operated.

The PCM will only operate the starter relay providing the following conditions are met:
- The ignition switch has been in the start position for a predetermined time
- The security response between the PCM and the instrument cluster (IC) has passed
- The engine is not running
- The transmission range switch is in the NEUTRAL or PARK position (vehicles fitted with automatic transmission)
- The clutch pedal is operated (USA vehicles fitted with manual transmission)

The starter relay remains energized until one of the following occur:
- The maximum cranking time is exceeded
- The PCM detects an engine running signal
- The ignition switch is no longer in the start position
- The transmission range switch is no longer in the NEUTRAL or PARK position (vehicles fitted with automatic transmission)
- The clutch pedal is released (USA vehicles fitted with manual transmission)

With the ignition switch in the start position, providing the PCM start conditions are met, the starter relay is energized and the engagement lever moves the pinion into mesh with the engine ring gear teeth. The electrical contacts within the solenoid complete the high power circuit and the starter motor operates to turn the engine.

The sequence of operation is as follows:
- Ignition switch in the start position
- Starter relay activated by the PCM
- Voltage provided to the starter motor solenoid
- Starter solenoid engages the drive pinion to the ring gear
- Starter solenoid switches the battery current to the starter motor
- The starter remains engaged until the PCM start conditions are no longer met