Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
System Overview: Overview
This document describes the principle design and function of a starter motor, regardless of the make.
The starter motor (6/25) cranks the engine to make starting possible. The starter motor is located on the transmission side of the engine block. The exact location depends on engine type. A solenoid causes a pinion to mesh with the crown wheel on the engine's flywheel/carrier. When the engine has started and engine speed exceeds starter motor speed, the pinion disengages. This prevents overcranking of the starter motor.
This type of starter motor is equipped with permanent magnets instead of field windings (except for the V8 engine, which has field windings).
The starter motor gives the greatest torque at low rpm at the same time as the voltage current through the starter motor is greatest.
The engagement time for the starter motor must not exceed 20-30 seconds. Longer engagement time results in the starter motor overheating and becoming damaged.
The starter motor solenoid is controlled by a starter motor relay (2/35). The relay, in turn, is controlled by the ignition switch (3/1) together with either the central electronic module (CEM) (4/56) or the engine control module (ECM). The engine management system of the vehicle determines whether the starter motor relay is regulated by the central electronic module (CEM) or the engine control module (ECM).
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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