2004 John Deer Buck Utility ATV 500, 500EX and 500EXT Service Manual, Page 34Get this manual
Go to next stepCheck spark plug electrode conditionGap is too big or spark plug condition is bad? Readjust gap (refer to "Specifications" section)Diagnose spark plug condition and replace it (refer to "Ignition System")Go to next stepCheck spark plug cable and ignition wireCable andor ignition wire is (are) damaged andor shows electrical failure? Replace damaged part(s)Go to next stepCheck ignition coil for damage andor electrical failureIs ignition coil damaged andor resistance value out of specification (refer to Specifications" section)? Is connector corroded or ignition coil shows electrical failure? Is wire harness brittle or hard (no connection)? Replace ignition coilClean connector area andor replace ignition coilReplace harnessGo to next stepCheck trigger coil on magneto for damage andor electrical failureSensor shows electrical failure andor damages? Connector is corroded? Resistance value is out of specification (refer to Specifications" section)? Replace magnetoClean and reconnectReplace magnetoGo to next stepCheck wire harness for cracks or other damagesHarness shows electrical failure andor other damages? Replace wire harness andor damaged wire sectionGo to next stepCheck magneto for damage andor electrical failureRadial position of rotor wrong due to broken woodruff key? Connector on magneto is damaged and or has electrical failure? Coating on stator winding is damaged? Resistance value is out of specification (refer to Specifications" section)? Replace woodruff keyRepair and clean contacts of connectorReplace magnetoCheck electronic moduleModule shows electrical failure or damages? Connectors are corroded? Electronic module has bad ground to the vehicle frame?