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: Rear Oxygen Sensor Voltage Curve

Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Malfunction Criteria	Threshold Value
Time needed for the rear oxygen sensor voltage to change up to 0.3 V after the fuel cut was deactivated	> 3750 time(s) X 32 ms

Time Needed for Diagnosis: 3750 time(s) X 32 ms

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