Services Types Causes/Failure Maintenance/ affected area Check engine light Failing oxygen sensor, Excessive air in air intake system, loose gas cap, bad spark plug/ignition coil, bad spark plug wires, Dirty catalytic converter, bad mass air flow sensor, bad condition of battery, EGR valve problem, parts that attached to the diagnostic part of engine Fender Repair Service Accident (Bent, Scratched or completely damaged fenders), impact load Repair damaged fender, washing, coloring Spark Plug Replacement spark plug degrading, dirty spark plugs, old spark plug, (trouble when starting, larger engine problem, loss of power and fuel economy) once a season, clean a spark plug from wire brush, replace the spark plug (don’t tight over) Battery Inspection & Testing overheated, overcharged temperature change, dust & dirt, loose fan belt, (headlights appear dimmer than normal, clicking sound while turning the key, engine backfires, battery system warning light is on, check engine light is on) once a season, use a voltmeter to test, Tight any loose cables, Replace the fan belt if it is cracked, replace (in case of failure), apply a thin coating of high temperature grease to posts and cable connections, check the State of Charge Indicator (voltage & charge)