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.
Starter motor
The starter motor is on the left-hand side of the engine by the air cleaner (ACL) housing. The starter motor is powered directly from the battery. There is a solenoid on the starter motor to close the circuit. The central electronic module (CEM) activates a relay in the relay box in the engine compartment to act on the solenoid. This supplies the solenoid with power and closes the circuit for the starter motor.
The starter motor turns when the key is turned to position III in the ignition switch.
There are different functions which prevent starting, depending on whether the car has an automatic or manual transmission. The central electronic module (CEM) also has an electronic immobilizer function which communicates with a transponder in the key. For further information about the immobilizer, see IMMOBILIZER (2001-2004) or IMMOBILIZER (2005-2007) .
- Cars with manual transmissions have a sensor in the clutch pedal. The clutch pedal must be depressed to allow starting (certain markets)
- In cars with type 4T65EV automatic transmissions, a signal is transmitted from the gear-shift position sensor to the transmission control module (TCM) which then sends a directly connected signal to the central electronic module (CEM)
- In cars with AW automatic transmissions, a directly connected signal is transmitted directly from the gear-shift position sensor to the central electronic module (CEM).
There are diagnostics for the relay for the starter motor.
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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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