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Home >> Subaru >> 2013 >> Legacy Base, Automatic CVT Trans >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DO) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P015A O2 Sensor Delayed Response - Rich To Lean (Bank 1 Sensor 1) >> Diagnostic Method 1
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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 Versus Time Graph
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. > 150 ms (AT model except for PZEV)
> 130 ms (MT model except for PZEV)
> 150 ms (PZEV AT model)
> 170 ms (PZEV MT model)
P015A
Average value of time necessary for λ to inverse the air fuel ratio to Rich → Lean → Rich. > 350 ms (AT model except for PZEV)
> 170 ms (MT model except for PZEV)
> 200 ms (PZEV AT model)
> 150 ms (PZEV MT model)
P015B

Time Needed for Diagnosis:  50 times of inversion

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

Judge as OK and clear the NG if 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. ≤ 150 ms (AT model except for PZEV)
≤ 130 ms (MT model except for PZEV)
≤ 150 ms (PZEV AT model)
≤ 170 ms (PZEV MT model)
P015A
Average value of time necessary for λ to inverse the air fuel ratio to Rich → Lean → Rich. ≤ 350 ms (AT model except for PZEV)
≤ 170 ms (MT model except for PZEV)
≤ 200 ms (PZEV AT model)
≤ 150 ms (PZEV MT model)
P015B

Time Needed for Diagnosis:  50 times of inversion