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Home >> Subaru >> 2015 >> XV Crosstrek Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Diagnostic Trouble Code (DTC) Detecting Criteria (Except Hybrid) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P015A: O2 Sensor Delayed Response - Rich To Lean (Bank 1 Sensor 1) >> Diagnostic Method 1

Diagnostic Method 1

Detect the malfunction depending on the average value of time necessary for λ to inverse the air fuel ratio from "Lean → Rich → Lean" to "Rich → Lean → Rich".

Fig 1: Sensor Output Graph (Diagnostic Method 1)
G08317433Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Malfunction Criteria Threshold Value DTC
Average value of time necessary for λ to inverse the air fuel ratio to Lean → Rich → Lean. > 1000 ms (CVT model)
> 1000 ms (MT model
P015A
Average value of time necessary for λ to inverse the air fuel ratio to Rich → Lean → Rich. > 1000 ms (CVT model)
> 1000 ms (MT model)
P015B

Time Needed for Diagnosis:  50 times of inversion

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