Q: What Does a Starter Motor Do?

The starter motor is a 12 volt, permanent magnet DC motor that engages a small drive gear on the starter with a larger ring gear that is attached to the flexplate, or flywheel. The flexplate is bolted to the rear of the engine crankshaft. When the starter drive gear engages with the flexplate ring gear, the starter drive spins the crankshaft to allow the engine to start. If the ignition system and fuel system are in good working order, the engine should fire up immediately.

No-starts (engine not starting) are one of the most common issues for vehicles that are taken to a repair shop.The root cause of this issue could be virtually anything.

No-start causes include:

• The vehicle battery
  
• The starter motor
  
• The starter relay
  
• The crankshaft position sensor
  
• The powertrain control module (PCM).
  

There are other potential causes than the ones I listed above. The PCM is likely the most expensive part, but is also the least likely cause. It is still a cause because I have replaced several in my career.

If your vehicle runs into any problems with its starter motor, contact a professional mechanic who can diagnose and fix your starting issue so you can get going once again.