Cranking System Symptom Diagnosis

Possible symptoms of starting system trouble are as follows:

•Starting motor does not run (or runs slowly).
•Starting motor runs but fails to crank engine.
•Abnormal noise is heard.
•Starting motor does not stop running.

Proper diagnosis must be made to determine in which of the battery, wiring harness, starting motor (including magnetic switch) and engine the cause of each trouble lies.

Before removing the starting motor, check the following items to identify most possible causes of trouble.

1)Condition of trouble

2)Tightness of battery terminals (including ground cable connection on engine) and starting motor terminals

3)Discharge of battery

4)Mounting of starting motor

Condition	Possible Cause	Action
Starting motor not running (No operating sound of magnetic switch)	Malfunction of CPP No.1 switch (M/T model)	Check CPP No.1 switch.
	Battery voltage is too low	Check battery.
	Impossible charging due to deteriorated battery	Replace battery.
	Poor battery terminal connection	Check terminal connection or replace battery.
	Poor ground cable connection	Tighten ground cable.
	Blown fuse	Replace fuse and check its circuit.
	Faulty magnetic switch	Check magnetic switch.
	Poor magnetic switch lead wire connector connection	Check connector connection.
	Open circuit in pull-in coil	Check pull-in coil circuit.
	Poor sliding of plunger and/or pinion	Check plunger and pinion.
	Faulty starting motor control relay	Check starting motor control relay.
	Faulty ST2 relay (ENG A-STOP model)	Check ST2 relay.
	Faulty ST3 relay (twin clutch system model)	Check ST3 relay.
	Faulty keyless push start system (keyless push start model)	Check keyless push start system.
	Faulty ignition switch (ignition switch model)	Check ignition switch.
	Faulty ENG A-STOP control module (ENG A-STOP model)	Check ENG A-STOP control module.
	Faulty TCM (twin clutch system model)	Check TCM.
Starting motor not running (Operating sound of magnetic switch heard)	Battery voltage is too low	Check battery.
	Impossible charging due to deteriorated battery	Replace battery.
	Poor battery terminal connection	Check terminal connection or replace battery.
	Poor ground terminal connection	Tighten ground cable.
	Defective magnetic switch	Check magnetic switch.
	Defective brushes and/or brush springs	Check brushes and brush springs.
	Faulty brush holder	Check brush holder.
	Burnt commutator	Check commutator.
	Short circuit between commutator and armature	Check commutator.
	Poor starting motor cable connection	Check starting motor cable connection.
	Open circuit between battery and magnetic switch	Repair circuit.
	Obstructed crankshaft rotation	Repair engine assembly.
Starting motor running but too slow (small torque)	Faulty magnetic switch	Check magnetic switch.
	Low battery voltage	Check battery.
	Impossible charging due to deteriorated battery	Replace battery.
	Poor battery terminal connection	Check terminal connection or replace battery.
	Short circuit between commutator and armature	Check commutator.
	Burnt commutator	Check commutator.
	Defective brushes and/or brush springs	Check brushes and brush springs.
	Defective brush holder	Check brush holder.
	Defective starter end frame bushing	Check starter end frame bushing.
Starting motor running, but not cranking engine	Worn pinion tip	Replace overrunning clutch.
	Poor sliding of overrunning clutch	Replace overrunning clutch.
	Slipping overrunning clutch	Replace overrunning clutch.
	Worn teeth of ring gear	Replace flywheel.
Noise	Abnormally worn bushing	Replace bushing.
	Worn teeth of pinion	Replace overrunning clutch.
	Worn teeth of ring gear	Replace flywheel.
Starting motor does not stop running	Faulty magnetic switch	Check magnetic switch.
	Faulty ignition switch (ignition switch model)	Check ignition switch.
	Faulty starting motor control relay	Check starting motor control relay.