HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OPERATION


BHE014000140T41

Operation Conditions

• The PCM operates the HO2S when the following conditions are met.

HO2S

Activation condition

Drive signal

Front
• After engine start
• After the engine has started and a fixed period of time has elapsed (the elapsed time period after the engine starts is determined by ECT).
• ECT is 5°C {41°F} or more.
• Battery positive voltage is 9 V or more and less than 16 V.
• MAF sensor is normal (no DTC is stored in PCM).
• The PCM outputs a duty signal.
• The element temperature is measured by the impedance of the HO2S and a duty ratio is determined.
Rear
• Starter is off
• After engine start
• After the engine has started and a fixed period of time has elapsed (the time period after the engine starts lenghtens if the ECT falls below 0°C {32°F}.
• ECT is 10°C {50°F} or more.
• Battery positive voltage is 9 V or more and less than 16 V.
• Charging efficiency is the fixed value or less, or during fuel cut.
• The PCM outputs a duty signal. However the duty signal is either 100% or 0%.