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HOMESERVICE MANUALSSUBARU2014IMPREZA SPORT LIMITEDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 13 (ENGINE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) DETECTING CRITERIA (HYBRID))DIAGNOSTIC TROUBLE CODE (DTC) DETECTING CRITERIADTC P015A: O2 SENSOR DELAYED RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1)DIAGNOSTIC METHOD 1
2014 Subaru Impreza Sport Limited

Diagnostic Method 1

2014 Subaru Impreza Sport LimitedSECTION Diagnostic Method 1
WARNING: This page is about a different car, the 2014 Subaru XV Crosstrek. However, it is still accessible from the selected car via links, so may be relevant.

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: Air Fuel Ratio Sensor Output Graph
G08317433Courtesy of SUBARU OF AMERICA, INC.
  • Abnormality Judgment 

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 P015A
Average value of time necessary for λ to inverse the air fuel ratio to Rich → Lean → Rich ≤ 300 ms P015B

Time Needed for Diagnosis:  50 times of inversion

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

  • Normality Judgment 

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 P015A
Average value of time necessary for λ to inverse the air fuel ratio to Rich → Lean → Rich > 300 ms P015B

Time Needed for Diagnosis:  50 times of inversion

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.