AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OPERATION [LF, L3]

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A/F sensor heater

Operation condition

•  The PCM operates the A/F sensor heater according to engine operation conditions as shown in the table below.

Drive duty ratio	Engine operation conditions
20 %	•  Engine coolant temperature 5 °C {41 °F} or less
35 %	•  At engine start •  During engine rotation except idling •  When a DTC indicating a damaged engine coolant temperature sensor, throttle position sensor or intake air temperature sensor is detected.
100 %	•  For a fixed period of time after engine start when the engine coolant temperature at engine start is 50 °C {122 °F} or less than the engine coolant temperature when the engine is stopped from a previous operation (differs from engine coolant temperature at engine start [lower engine coolant temperature→longer time])

Inhibition conditions

•  When all of the following conditions are met (for 6 s):

―  During torque reduction execution

―  Engine speed is 5,000 rpm or more.

―  Throttle opening angle 85 % or more

•  Engine speed 4,000 rpm or more

•  During high load

•  When A/F sensor heater is damaged

•  When ignition switch is turned to the ON position while engine is stopped

HO2S heater

Operation conditions

•  When all of the following conditions are met:

―  After fixed period of time from engine start

―  Engine speed is less than 4,000 rpm.

―  Except during torque reduction execution

―  During low load