AIR FUEL RATIO (A/F) SENSOR, HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OPERATION [L8, LF, L3]

id0140a5782200

Pre-heater Control (A/F sensor Heater)

Operation condition
• From the engine start to the threshold time: The PCM supplies voltage of approx. 6 V.

Cycle Estimated Control

Operation conditions
• The PCM operates the A/F sensor or HO2S heater when the following conditions are met.

A/F sensor heater

Drive duty ratio | Engine operation condition
--- | ---
0% | • Ignition switch is 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

Drive duty ratio | Engine operation condition
--- | ---
0% | • Ignition switch is 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