For 1990-2009 cars

Checks | Causes
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There is a high-pitched whine during cranking, before the engine fires, but the engine cranks and fires okay. | The distance is too great between the starter pinion and the flywheel.
There is a high-pitched whine after the engine fires, while the key is being released. The engine cranks and fires okay. This intermittent complaint is often diagnosed as "starter hang-in" or as "solenoid weak". | The distance is too small between the starter pinion and the flywheel. Flywheel runout contributes to the intermittent condition.
A loud whoop occurs after the engine fires while the starter is still held engaged. A siren sound occurs if the engine is accelerated, while the starter is engaged. | The probable cause is an inoperative starter motor clutch. A new clutch will often correct this problem.
A rumble, a growl or, in severe cases, a knock occurs, when the starter is coasting down to a stop after starting the engine. | The probable cause is a bent or an unbalanced starter motor armature. A new armature will often correct this problem.