Chevrolet Equinox Service Manual: Starting System Description and Operation Starting System

The starter motors are non-repairable starter motors. They have pole pieces that arearranged around the armature. Both solenoid windings are energized. The pull-in windingcircuit is completed to the ground through the starter motor. The windings work togethermagnetically to pull and hold in the plunger. The plunger moves the shift lever. Thisaction causes the starter drive assembly to rotate on the armature shaft spline asit engageswith the flywheel ring gear on the engine. Moving at the same time, the plunger alsocloses the solenoid switch contacts in the starter solenoid. Full battery voltageis applied directly to the starter motor and it cranks the engine.

As soon as the solenoid switch contacts close, current stops flowing thorough thepull-in winding because battery voltage is applied to both ends of the windings. Thehold-in winding remains energized. Its magnetic field is strong enough to hold theplunger, shift lever, starter drive assembly, and solenoid switch contacts in placeto continue cranking the engine. When the engine starts, pinion overrun protects thearmature from excessivespeed until the switch is opened.

When the ignition switch is released from the START position, the START relay opensand battery voltage is removed from the starter solenoid S terminal. Current flowsfrom the motor contacts through both windings to the ground at the end of the hold-inwinding. However, the direction of the current flow through the pull-in winding isnow 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. Thisaction of the windings, along with the help of the return spring, causes the starterdrive assembly to disengage and the solenoid switch contacts to open simultaneously.As soon as the contacts open, the starter circuit is turned off.

When the ignition switch is placed in the Start position, a discrete signal is suppliedto 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 thatCRANK 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. Whenthisoccurs, battery positive voltage is supplied through the switch side of the crankrelay to the S terminal of the starter solenoid.

K20Engine Control ModuleC1BatteryKR27Starter RelayK9Body Control ModuleT12Automatic Transmission AssemblyM64Starter MotorS39Ignition SwitchHard-Wired

Serial Data - GMLAN High Speed

K20-Engine Control Module

C1-Battery

KR27-Starter Relay

K9-Body Control Module

T12-Automatic Transmission Assembly

M64-Starter Motor

S39-Ignition Switch