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Home >> Subaru >> 2013 >> Forester X, Standard Trans >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DO) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P014C O2 Sensor Slow Response - Rich To Lean (Bank 1 Sensor 1) >> Diagnostic Method 1
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Diagnostic Method 1

Detect the malfunction by checking "Cumulative value of time when λ changes from lean → rich" in comparison to "Time during which diagnosis is in progress".

Fig 1: Sensor Output And Accumulated Time Graph
G08570547Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

JUDGMENT VALUE

Malfunction Criteria Threshold Value DTC
(Cumulative value of time when λ changes from lean → rich) / (Time during which diagnosis is in progress) < 0.39 (except for PZEV model)
< 0.39 (PZEV model)
P014C
> 0.61 (AT model)
> 0.63 (PZEV model)
P014D

Time Needed for Diagnosis:  90 seconds

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
(Cumulative value of time when λ changes from lean → rich) / (Time during which diagnosis is in progress) ≤ 0.39 (except for PZ model)
≤ 0.39 (PZ model)
P014C
≥ 0.61 (except for PZ model)
≥ 0.63 (PZ model)
P014D

Time Needed for Diagnosis:  90 seconds