HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OPERATION[ZJ, ZY, Z6]

id0140b1180200

Without Throttle Valve Actuator

Front HO2S

Operation condition

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

Drive duty ratio

Engine operation conditions

30 %

•  At engine start

•  During engine rotation except idling

•  Engine coolant temperature is 5°C {41°F} or less.

•  When a DTC indicating a damaged ECT sensor, TP sensor or IAT 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 water temperature→longer time]).

Drive duty ratio	Engine operation conditions
30 %	• At engine start • During engine rotation except idling • Engine coolant temperature is 5°C {41°F} or less. • When a DTC indicating a damaged ECT sensor, TP sensor or IAT 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 water temperature→longer time]).

Inhibition conditions

• During torque reduction execution

• Engine speed 4,300 rpm or more

• During high load

• Engine stopped

Rear HO2S

Operation condition

• When all of the following conditions are met:

― After fixed period of time from engine start

― Engine speed is less than 2,700 rpm

― Throttle valve opening angle is less than 10%

― Intake air amount exceeds the specified value

― Except during TCS control

With Throttle Valve Actuator

Operation condition

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

Front

Drive duty ratio

Engine operation conditions

The energization duty ratio is determined from the element temperature measured by the HO2S element impedance.

• At engine start

• While the engine is running except during idling.

• Engine coolant temperature is 5 °C {41 °F} or less.

• When a DTC indicating a malfunctioning ECT sensor, TP sensor, or IAT sensor is detected

• For a fixed period of time after engine start if the engine coolant temperature at engine start is 50 °C {122 °F} lower or more than the engine coolant temperature when the engine is stopped from a previous operation (differs depending on the engine coolant temperature at engine start [lower water temperature→longer time]).

Rear

Drive duty ratio	Engine operation conditions
0 %	• Engine coolant temperature less than -10 °C {14 °F} • High load • Engine is stopped
40 %	• At engine start • While the engine is running except at high load • Engine coolant temperature is -10 °C {14 °F} or more. • DTC for the following parts is detected: ― ECT sensor ― TP sensor ― IAT sensor
50—90 %	• For a fixed period of time after engine start if the engine coolant temperature at engine start is 12 °C {54 °F} lower or more than the engine coolant temperature when the engine is stopped from a previous operation (differs depending on the engine coolant temperature at engine start [lower water temperature→longer time]).