Causes of car starter failure

Normal wear can cause a starter to fail. Aside that, there are other root causes like bad solenoid, bad electric motor, bad pinion gear, bad connection and so on.

The starter (some call it Kickstarter) is a very important part of a vehicle. A faulty one can make a car not to start.

It is worse for cars with automatic transmissions because they cannot be rolled to start like vehicles with manual transmission.


Reasons why starters fail

1. Normal wear

Normal wear and age can cause a starter to fail. This will happen to every starter when they age.

2. Worn brushes

When the brushes of a starter motor is worn, there won't be adequate electrical contact. This will make the motor to be slow or not run at all.

3. Faulty solenoid

The solenoid is an engaging relay that switches power to the main starter motor ON and OFF. When it is working, you hear a click when it engages. When it is faulty, power will not go to the starter motor. Here is a teardown of starter solenoid and ways the solenoid can fail.

4. Faulty pinion gear

A faulty pinion gear or starter pinion will make a starter not to engage.

5. Faulty electrical motor

When the electrical motor is supplied with electrical power, the power is converted to mechanical energy and the starter turns the crankshaft through the flywheel. The electrical coil of the motor can burn out or the split rings can be damaged.

6. Faulty trigger cable/connection

The trigger wire is a signal wire from the ECU, ignition switch or security module. It carries the signal that makes the solenoid to engage. If it is bad or has a poor connection, the starter will not work.

7. Faulty starter fuse

Many latest model cars have starter fuses. A bad fuse will make it not to work.

8. Weak car battery

A car battery that is weak will increase the stress on the starter. It can make the starter to heat up during start attempts.

9. Weak charging system

A weak charging system will make the battery to not charge well which will affect the starter.

10. Bad electrical connections

This can happen because of partial contacts, corrosion or bad plugs/connectors.

11. Poor installation

If the bolts that are meant to secure the starter are loose, the starter will not be properly grounded. This can cause damage to it.

12. Oil leaks

Oil leaks from orher parts of the engine will reduce electrical contact at the brushes and contacts in the starter. 

13. Continuous or frequent cranking

When a car fails to start, continuous or frequent cranking will make the starter to overheat and fail.

14. Stiff engine

An engine that has mechanical problem and is stiff will overwork the starter and might burn it if there is continuous attempt to start the engine.

15. Water in starter motor assembly

If water enters the starter motor assembly, vit will affect electrical conduction and also cause corrosion thereby damaging it.