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

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Pre-heater Control (A/F sensor Heater)

Operation condition

• From the engine start to the threshold time: The PCM supplies voltage of approx. 4.5 V.

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)

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 4,500 rpm or more

•  Charging efficiency is at the set value or more
(charging efficiency varies according to engine speed)

100 %

•  Except for 0 % condition

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 4,500 rpm or more • Charging efficiency is at the set value or more (charging efficiency varies according to engine speed)
100 %	• Except for 0 % condition