Diagnostic Method

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

Fig 1: Rear Oxygen Sensor Voltage Starting To Drop - Diagnostic Method

Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

JUDGMENT VALUE SPECIFICATION

Malfunction Criteria	Threshold Value
Time needed for the rear oxygen sensor voltage to change up to 0.5 V after the fuel cut started	> 4000 ms

Time needed for diagnosis: 5 seconds

Malfunction indicator light illumination: Illuminates as soon as a malfunction occurs.