V

Richer

Leaner

Small changes in the air/fuel ratio from the stoichiometric point radically changes the voltage signal. This type of oxygen sensor is sometimes referred to as a narrow range sensor because it cannot detect the small changes in the exhaust stream oxygen content produced by changes in the air/fuel mixture. The ECM will continuously add and subtract fuel producing a rich/lean cycle. Refer to Closed Loop Fuel Control in the Fuel Injection section for more information.

NOTE: Think of the oxygen sensor as a switch. Each time the air/fuel ratio is at stoichiometry (14.7: 1) the oxygen sensor switches either high or low.

The oxygen sensor will only generate an accurate signal when it has reached a minimum operating temperature of 400'C (7500F). To quickly warm up the oxygen sensor and to keep it hot at idle and light load conditions, the oxygen sensor has a heater built into it. This heater is controlled by the ECM. See Oxygen Sensor Heater Control for more information.

Types of Abnormal Signals

Oxygen Signals -,_

Types of Abnormal Signals

Oxygen Signals -,_

T852f389/T852f390 T852f391/T852f392

T852f389/T852f390 T852f391/T852f392

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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