Starting and Charging: Description and Operation

Description

Starting
The starting system on the vehicle comprises a 12 volt starter motor which drives the engine to start the combustion process. The starter converts electrical energy into mechanical power. The vehicle electrical system must be capable of supplying sufficient power to enable the engine to be cranked.

Charging
The charging system comprises a battery and an alternator. The battery must be of a sufficient capacity to operate the starter motor and operate various electrical systems in the vehicle. The alternator charges the battery when the engine is running and increases its output as demand on the battery increases.

The instrument pack incorporates a charge warning lamp which illuminates when there is no output or a low output from the alternator.

Operation
Feed from the positive battery terminal (C0192) is supplied to fusible link 1, fusible link 3, fuse 10 and the main relay (C0632) on an R wire. All are located within the engine compartment fuse box. The battery (C0192) also provides a feed to the starter motor solenoid (C0178) on an R wire.

Fusible link 1 is connected in series with fusible link 7, which is also located within the engine compartment fuse box.

Fusible link 3 (C0571) is connected to the ignition switch (C0028) by an N wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 18, fuse 22, and fuse 41 of the passenger compartment fuse box (C0588) on a G wire.

When the ignition switch is turned to the 'crank' position, current flows across the switch (C0028) to fuse 5 of the passenger compartment fuse box (C0588) on a WR wire.

Starting Main Relay
Fuse 22 of the passenger compartment fuse box (C0580) provides an ignition feed to the Engine Control Module (ECM) (C0913) on a W wire. When the ECM receives this feed, it energises the main relay by providing an earth path for the relay coil (C0576) on a WK wire. The energised main relay is now able to provide a feed to the fuel pump relay. The fuel pump relay is also located in the engine compartment fuse box.

Inertia Switch
Fuse 10 of the engine compartment fuse box (C0575) provides a constant battery feed to the inertia switch (C0123) on a G wire. The inertia switch is a normally closed switch. If the inertia switch hasn't been tripped, current flows across the switch (C0123) to the fuel pump relay (C0575) on a GU wire.

The inertia switch (C0123) also provides a feed to the Central Control Unit (CCU) (C0428) on a UG wire.

Fuel Pump Relay
The fuel pump relay coil receives a feed from the energised main relay (see above ). The earth path for the relay coil (C0575) is controlled by the ECM (C0913) on a BP wire. The ECM will energise the fuel pump relay when it receives an ignition feed from fuse 22 of the passenger compartment fuse box (C0581) on a W wire.

The energised fuel pump relay (C0572) provides a feed to the fuel pump (C0114) on a WP wire. The pump (C0114) is earthed on a B wire.

Starter Relay
Fuse 5 of the passenger compartment fuse box (C0581) provides an ignition switch 'crank' feed to the immobilisation ECU (C0059) on a WR wire. If the vehicle has been successfully re-mobilised, the immobilisation ECU (C0059) provides a feed to the starter relay coil (C0576) on a RW wire. The starter relay is located in the engine compartment fuse box, and is earthed (C0576) on a B wire. A battery feed from fusible link 7 is now able to flow across the starter relay switch contacts (C0572) to the starter motor solenoid (C0179) on an NR wire.

Starter Motor and Starter Motor Solenoid
The starter motor solenoid coil (C0179) receives a feed from the energised starter motor relay (C0572) on an NR wire (see above ). The energised starter motor solenoid allows a battery feed (C0178) to flow across the switch contacts and power the starter motor.

Central Control Unit (CCU)
The CCU (C0428) receives a feed from the inertia switch (C0123) via the engine compartment fuse box (C0576) on a UG wire. If this feed is removed due to the inertia switch being tripped, the CCU will unlock all of the doors.

NOTE: The CCU will only unlock all doors if the ignition switch is in the 'ignition' position.

The CCU (C0429) also provides a signal feed to the immobilisation ECU (C0059) on a KN wire. This signal feed informs the immobilisation ECU to energise the starter relay.

Charging

Alternator
Fusible link 1 of the engine compartment fuse box (C0826) provides a constant battery feed to the alternator (C0183) on an R wire. Fuse 41 of the passenger compartment fuse box (C0583) provides an ignition feed to the alternator (C0185) on a W wire.

When the engine is started, the magnetised rotor within the stator windings generate 3 phase alternating current (ac) and voltage that rises rapidly with rotor speed. The field diodes in the rectifier pack convert the ac current into direct current (dc). Output current from the field diodes supplements the initial current flowing through the field windings. This causes an increase in the magnetic influence of the rotor, resulting in self-exitation of the alternator. The field current increases with rotor speed and thus increases the generated current and voltage until the alternator is fully excited.

When the engine is running, the alternator (C0185) supplies the ECM (C0914) with a Pulse Width Modulated (PWM) signal on a WR wire. The ECM uses the PWM signal to calculate electrical load on the alternator, and controls idle speed accordingly.

The alternator (C0183) charges the battery by providing current via fusible link 1 of the engine compartment fuse box (C0826 & C0632) to the battery positive terminal (C0192) on an R wire.

Ignition/No Charge Warning Lamp
Fuse 18 of the passenger compartment fuse box (C0589) provides an ignition feed to the ignition/no charge warning lamp (C0233) on a G wire. Current flows across the lamp (C0233) and is provided an earth path by the alternator (C0185) on an NY wire. The warning lamp will now illuminate.

When the alternator is charging, it provides a feed to the warning lamp (C0233) on the NY wire. Because the potential difference across the bulb is 0 V, the lamp will now extinguish.