1.CHECK GROUND CONNECTION
 
 2.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
 
 3.DETECT MALFUNCTIONING PART
 
 4.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
 
 5.CHECK INTERMITTENT INCIDENT
 
 6.REPLACE AIR FUEL RATIO (A/F) SENSOR 1