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

id0140001802c0

Operation Conditions

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

Front

Drive duty ratio

Engine operation conditions

Determines the duty ratio by measuring the element temperature with the HO2S heater element impedance
• At engine start
• During engine rotation except idling
• Engine coolant temperature is 5°C {41°F} or less.
• When a DTC indicating a malfunction in one of the following sensors is detected.
- ECT sensor
- TP sensor
- IAT sensor
• 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]).

Rear

Drive duty ratio

Engine operation conditions

0%
• Engine coolant temperature is -10°C {14°F} or less.
• Heavy load condition
• While engine is stopped
40%
• At engine start
• During engine rotation except under heavy load
• Engine coolant temperature is -10°C {14°F} or more.
• When a DTC indicating a malfunction in one of the following sensors is detected.
- ECT sensor
- TP sensor
- IAT sensor
50-90%
• For a fixed period of time after engine start when the engine coolant temperature at engine start is 12°C {54°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]).