AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OPERATION [L8, LF, L5]

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Pre-heater Control (A/F Sensor Heater)

Cycle Estimated Control

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
0 %	•  Ignition off •  Engine is stopped •  At engine start (cranking)
Approx. 50 % (Determines the duty ratio by measuring the element temperature with the A/F sensor heater element impedance)	•  After engine warm up (duty ratio varies according to battery condition)

HO2S heater

Operation condition

•  The PCM operates the HO2S heater according to engine operation conditions as shown in the table below.

Drive duty ratio	Engine operation conditions
0 %	•  Ignition off •  Engine is stopped •  Within a fixed period of time after engine start (time varies according to engine coolant temperature) •  Engine speed is 3,900 rpm or more •  Charging efficiency is at the set value or more (charging efficiency varies according to engine speed)
30 %	•  Drive duty ratio is other than 0 % or 100 %
100 %	•  During KOEO self test execution