Circuit Operation - Starting System

When the ignition switch is moved to the START position and the gear selector lever is in PARK or NEUTRAL, battery voltage is supplied to the normally-open contacts of the starter enable relay. Voltage is also supplied through tile park/neutral position switch to the starter enable relay coil. At the same time, a start request is sent to tile PASS-Key(R) II decoder module. If correct PASS-Key(R) II system resistance is sensed, then the PASS-Key(R) II decoder module energizes the starter enable relay by grounding on one side of the relay coil. (The PASS-Key(R) II decoder module also provides the PCM cranking fuel enable signal. Refer to Antitheft and Alarm Systems Antitheft and Alarm Systems

Once the starter enable relay is energized, the normally-open contacts close, completing the circuit to the starter solenoid. When the starter solenoid circuit is completed, both the hold-in and pull-in windings are energized. The circuit through the pull-in winding is completed to 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 as it engages with the flywheel ring gear on the engine. Rotating 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 through 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, and starter drive assembly solenoid switch contacts in place to continue cranking the engine.

When the ignition switch is released from the START position, battery voltage is removed from the PPL wire and the junction of the two windings. Current flows from the motor contacts through both windings to 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 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.


Starter Inhibit Operation
The powertrain has a starter inhibit function that prevents engagement of the starter once the engine is running. The PCM checks for an engine RPM signal greater than engine cranking speed. Once the engine is running, the PCM provides a ground through the starter inhibit circuit (CKT 1433) of the PCM. This ground allows the starter inhibit control in the PASS-Key(R) H decoder module to energize, which opens the starter enable relay control.

Once the relay control is prevented from closing, any ignition key input is ignored; the starter is prevented from engaging while the engine is running.