Actron CP9087 Service Manual

Contents

Actron CP9087 Service Manual Manual pdf 26 page image

2-18Testing SensorsSection 2Location The sensor is threaded into the exhaust manifold togive it direct contact with the exhaust gases.How it isused?The computer uses this sensor to calculateoptimum air/fuel mixture for low emissions andgood fuel economy. If the sensor indicates a richexhaust (not enough oxygen because of too muchfuel), the computer will compensate by reducingfuel delivery. If the computer receives a lean signal(too much oxygen because of too little fuel), it willincrease fuel delivery. NOTE: Some vehicles usemore than one oxygen sensor.What is It? The oxygen sensor is a zirconium dioxide ceramicmounted in the tip of a threaded metal housing.The tip is perforated to protect the sensing elementbut still allow exhaust gases to pass through.The sensor produces a voltage signal based on theamount of oxygen it contacts. A low voltageindicates a lean exhaust (too much oxygen). Ahigher voltage signals a rich exhaust (not enoughoxygen).The sensor must be very hot to operate: 349(C(660(F). Many have 2-wire heating elements built-in to quicken the warm-up time.Typical Oxygen Sensor