LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2019 >> WRX Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (Except For STI) (1 Of 4) >> Diagnostic Procedure With Diagnostic Trouble Code (DTC) >> DTC P014C: A/F/O2 Sensor Slow Response - Rich To Lean Bank 1 Sensor 1 >> Diagnostic Method 1
April 5, 2026: LEMON Manuals is launched! Read the announcement.

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".

G13264299Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

JUDGMENT VALUE SPECIFICATION

Malfunction Criteria Threshold Value DTC
(Cumulative value of time when λ changes from lean → rich)/(Time during which diagnosis is in progress) < 0.38 P014C
and Average value of time necessary for λ to inverse the air fuel ratio to Lean → Rich → Lean > 0.01 s  
(Cumulative value of time when λ changes from lean → rich)/(Time during which diagnosis is in progress) > 0.61 P014D
and
Average value of time necessary for λ to inverse the air fuel ratio to Lean → Rich → Lean
> 0 s  

Time needed for diagnosis: 

120 s (CVT model)

90 s (MT model)

Malfunction indicator light illumination:  Illuminates when malfunction occurs in 2 continuous driving cycles.