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.
Starting System
The starting system consists of the following components:
- Starter motor
- Starter motor relay - part of smart junction box (SJB)
- Transmission range (TR) sensor - automatic transmission
- Clutch cutoff switch - manual transmission
- Battery
- Ignition switch
When the key is placed in the START position, the starter solenoid is energized and a magnetic field is created in the starter solenoid windings. The iron plunger core is drawn into the starter solenoid coil, and a drive lever and pin connected to the starter drive engages the drive pinion gear to the flexplate/flywheel ring gear. When the plunger is pulled all the way in, its contact disc closes the circuit between the battery and the starter motor solenoid feed terminals. This sends current to the motor, and the drive pinion gear cranks the flexplate/flywheel to start the engine. When current flows to the starter motor, the starter solenoid pull-in coil is bypassed, and the hold-in coil keeps the drive pinion gear engaged with the flywheel until the ignition switch is released from the START position.
An overrunning clutch in the starter drive protects the starter motor from excessive speeds during the brief period before the driver releases the ignition switch from the START position as the engine starts.
Vehicles equipped with a manual transaxle have a clutch cutoff switch mounted on the clutch pedal bracket. The clutch cutoff switch prevents operation of the starter motor unless the clutch is fully depressed.
Vehicles equipped with an automatic transmission have a TR sensor mounted on the transaxle. The TR sensor prevents operation of the starter motor unless NEUTRAL or PARK is selected.
NO RELATED
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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.