NANO

646 ELECTRICAL DIAGNOSTIC PROCEDURES & INFORMATION Before removing starter motor for repair, the following checks should be made, • Battery: To determine the condition of battery, follow the testing procedure outlined in the battery manufactures service bulletin. Ensure the battery is fully charged. • Wiring: Inspect the wiring for damages. Inspect all connections to the cranking motor, solenoid switch, ignition switch or other control switch and battery, including all ground connections. Clean using smear petroleum jelly and tighten all connections as required. • Solenoid & control switches: Inspect all switches to determine their condition. With switches closed, use a voltmeter to check circuit continuity .Replace defective switches and wiring required, CONDITION POSSIBLE CAUSES CORRECTION/REFERENCE ITEM 1) Pinion fails to engage. Defective solenoid switch. Check solenoid and Replace. Armature does not rotate. 2) Armature fails to rotate or a) Brushes worn-out and not Replace brushes, if found to be rotates slowly and the starter making proper contact with worn-out. does not crank the engine commutator. though pinion has engaged b) Dirty, oily or badly burnt Remove dirt or oil. If commutator is with ring gear commutator. burnt, replace armature. c) Starter terminal or brush box Remove the starter for further having earth fault. Defective investigations and replace parts as Solenoid Switch. Defective found to be necessary. Armature / Field Coils. 3) Armature rotates but pinion Pinion sticky on shaft. Shaft splines and the pinion internal fails to engage. splines to be cleaned and lubricated 4) Armature rotates, pinion fails Clutch slip. Replace drive assy. to engage. 5) Starter continues to run a) Sticky solenoid switch on Disconnect starter cable after the solenoid switch is dashboard immediately at starter battery released. terminal. Replace Starter switch. b) Sticky solenoid switches contacts Replace solenoid, if found faulty. c) Pinion / Ring gear fouled or Clean thoroughly, deburring pinion damaged. and ring gear by filing. Replace, if necessary. 6) Low free speed and high a) Too much friction-worn out Replace the bush bearings or faulty current drawn. bush bearings, bent armature parts. shaft or loses pole pieces allowing armature to drag misalignment in assembly b) Shorted armature. Replace armature if shorted c) Ground armature. Replace defective part. 7) Failure to operate with high Direct ground in the terminals Replace the defective part / current drawn insulation. 8) Failure to operate with no a) Armature open circuited . Replace armature after ensuring current drawn Solenoid switch contact Ok. open circuit. b) Broken brush springs, worn Remove dirt or oil. If commutator is brushes, high insulation burnt, replace armature. between commutator bars. 9) Low free speed and current High terminal resistance due to poor Replace defective part after drawn. connection, defective leads,dirty checking out loose joints/broken commutator and cause listed in 4. parts.