Chevrolet Sonic Repair Manual: Starting System Description and Operation
The starter motors are non-repairable starter motors. They have pole pieces that are arranged around the armature. Both solenoid windings are energized. The pull-in winding circuit is completed to the ground through the starter motor. The windings work together magnetically to pull and hold in the plunger. The plunger moves the shift lever. This action causes the starter drive assembly to rotate on the armature shaft spline as it engages with the flywheel ring gear on the engine. Moving at the same time, the plunger also closes the solenoid switch contacts in the starter solenoid. Full battery voltage is applied directly to the starter motor and it cranks the engine.
As soon as the solenoid switch contacts close, current stops flowing thorough the pull-in winding because battery voltage is applied to both ends of the windings. The hold-in winding remains energized. Its magnetic field is strong enough to hold the plunger, shift lever, starter drive assembly, and solenoid switch contacts in place to continue cranking the engine. When the engine starts, pinion overrun protects the armature from excessive speed until the switch is opened.
When the ignition switch is released from the START position, the START relay opens and battery voltage is removed from the starter solenoid S terminal. Current flows from the motor contacts through both windings to the ground at the end of the hold-in winding. However, the direction of the current flow through the pull-in winding is now opposite the direction of the current flow when the winding was first energized.
The magnetic fields of the pull-in and hold-in windings now oppose one another. This action of the windings, along with the help of the return spring, causes the starter drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.
- Circuit Description (Key Start)
-
When the ignition switch is placed in the Start position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the Start position. The BCM then sends a message to the engine control module (ECM) notifying it that CRANK has been requested. The ECM verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies 12 V to the control circuit of the crank relay. When this occurs, battery positive voltage is supplied through the switch side of the crank relay to the S terminal of the starter solenoid.
- Starting System Block Diagram
K20 Engine Control Module C1 Battery KR27 Starter Relay K9 Body Control Module T12 Automatic Transmission Assembly M64 Starter Motor S39 Ignition Switch
Starter Replacement (LUW)
Removal Procedure
Disconnect the negative battery cable. Refer to Battery Negative Cable
Disconnection and Connection.
Raise and support the vehicle. Refer to Lifting and Jacking ...
Battery System
...
Other materials:
Rear Compartment Lid Rear Hinge Replacement
Rear Compartment Lid Rear Hinge Replacement
Callout
Component Name
Preliminary Procedures
Remove the rear window trim panel. Refer to Rear Window Panel Trim
Replacement.
Remove the rear compartment lid. Refer to Rear Comp ...
Front Wheel Drive Shaft Seal Replacement - Left Side
Front Wheel Drive Shaft Seal Replacement - Left Side
Callout
Component Name
Preliminary Procedures
Raise and support the vehicle. Refer to Lifting and Jacking the
Vehicle.
Remove the left wheel drive shaft. Refer to Front ...
Selector and Shift Lever Cable Bracket Replacement
Removal Procedure
Remove the battery tray. Refer to
Battery Tray Replacement.
Disconnect the shift lever and selector lever cable
end (1) from the transmission shift lever and selector lever.
Pull the cable retainers (2) to release the shift
le ...
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