Diagnostic Method

Detect the trouble by calculating the time from the completion of the fuel cut to the beginning of the rear oxygen sensor voltage starting to rise.

Fig 1: Diagnostic Method For Rear Oxygen Sensor Output Voltage

Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

MALFUNCTION CRITERIA

Malfunction Criteria

Threshold Value

Output voltage value of rear oxygen sensor

< 0.2 V

Elapsed time⁽¹⁾

> Map

⁽¹⁾	Elapsed time: The time since the λ became less than 1 after the end of fuel cut

Map

Amount of intake air (g/s)	15	16	18	40
Elapsed time (s)	4	4	4	4

Time Needed for Diagnosis: Less than 1 second

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.