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

id0140c4782200

A/F sensor heater

• 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

Determines the duty ratio by measuring the element temperature with the A/F sensor heater element impedance

•  Engine coolant temperature reaches 15°C {59°F} after 18 s have elapsed since engine start (drive duty ratio: 1.1—20%)

•  Engine coolant temperature sensor malfunction (drive duty ratio: 1.1—67%)

•  Under conditions except above (drive duty ratio: 67—100%)

Drive duty ratio	Engine operation conditions
Determines the duty ratio by measuring the element temperature with the A/F sensor heater element impedance	• Engine coolant temperature reaches 15°C {59°F} after 18 s have elapsed since engine start (drive duty ratio: 1.1—20%) • Engine coolant temperature sensor malfunction (drive duty ratio: 1.1—67%) • Under conditions except above (drive duty ratio: 67—100%)

HO2S heater

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

Drive duty ratio

Engine operation conditions

0%

•  Engine coolant temperature is -10°C {14°F} or less

•  Battery voltage is less than 9V or the battery voltage is 16V or more

•  Heavy load condition

•  While engine is stopped

•  During a certain period after engine start

40%

•  After a certain period has elapsed since engine start

•  During engine rotation except under heavy load

•  Engine coolant temperature is -10°C {14°F} or more

•  DTC has been stored for the ECT 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]).

Drive duty ratio	Engine operation conditions
0%	• Engine coolant temperature is -10°C {14°F} or less • Battery voltage is less than 9V or the battery voltage is 16V or more • Heavy load condition • While engine is stopped • During a certain period after engine start
40%	• After a certain period has elapsed since engine start • During engine rotation except under heavy load • Engine coolant temperature is -10°C {14°F} or more • DTC has been stored for the ECT 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]).