LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2019 >> Ascent Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (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 >> Diagnosis 1
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis 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".

G13202453Courtesy of SUBARU OF AMERICA, INC.

Judge as NG when the following conditions are established.

Judgment value

JUDGMENT VALUE SPECIFICATION (P014C)

Malfunction Criteria Threshold Value
(Cumulative value of time when λ changes from lean → rich)/(Time during which diagnosis is in progress) Less than 0.4
and
Average value of time necessary for λ to inverse the air fuel ratio to Lean → Rich → Lean
More than 10 ms
JUDGMENT VALUE SPECIFICATION (P014D)

Malfunction Criteria Threshold Value
(Cumulative value of time when λ changes from lean → rich)/(Time during which diagnosis is in progress) More than 0.6
and
Average value of time necessary for λ to inverse the air fuel ratio to Lean → Rich → Lean
More than 10 ms

Time needed for diagnosis:  120 s

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