Diagnostic Method

Detect the trouble by calculating the response time of the rear oxygen sensor during fuel cut.

Fig 1: Rear Oxygen Sensor/Response Time Graph

Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

Malfunction Criteria	Threshold Value
Time needed for rear oxygen sensor voltage to change from 0.5 V to 0.2 V	> 837 ms

Time Needed for Diagnosis: 5000 ms

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