If your engine won't turn over at all (the starter motor doesn't engage), the problem is likely in one of these areas:
* Battery: The most common cause. A dead or weak battery will prevent the starter motor from working. Check the battery voltage.
* Starter Motor: The starter motor itself could be faulty. This could be due to a bad connection, a seized motor, or internal failure.
* Starter Solenoid: This is the electrical switch that engages the starter motor. A faulty solenoid will prevent the starter from receiving power.
* Wiring: There could be a broken or corroded wire in the circuit between the battery, the ignition switch, the starter solenoid, and the starter motor.
* Ignition Switch: The ignition switch itself could be faulty and not sending power to the starter circuit.
* Neutral Safety Switch (Automatic Transmission): In automatic transmission vehicles, this switch prevents the engine from starting unless the gear selector is in Park or Neutral. A faulty switch can prevent the engine from cranking.
To troubleshoot:
1. Check the battery voltage: Use a voltmeter to check if the battery has sufficient voltage.
2. Listen for clicking sounds: When you turn the key, do you hear clicking from the starter solenoid? This could indicate a low battery or a faulty solenoid.
3. Check all connections: Inspect all connections related to the battery, starter, and solenoid for corrosion or looseness.
4. Attempt to jump-start the vehicle (carefully!): If the battery is the problem, this might get the engine to crank. But don't jump-start if there are other electrical problems; you could damage components.
Only after you've ruled out the more common causes above should you suspect the camshaft position sensor. A faulty CMP sensor will usually let the starter crank, but it will fail to fire the engine. It won't prevent the starter motor from functioning.
