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Home >> Subaru >> 2015 >> WRX Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DOTC) (Except STI) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P0171 System Too Lean (Bank 1) >> Diagnostic Method

Diagnostic Method

Compare the diagnostic value with the threshold value, and if a condition meeting the criteria continues for 10 s x 3 times or more, judge that there is a fault in the fuel system.

Judgment Value 

JUDGMENT VALUE SPECIFICATION

Malfunction Criteria Threshold Value
faf x (1+flaf) > 1.35
faf = Main feedback compensation coefficient  
flaf = main feedback learning compensation coefficient  

Time Needed for Diagnosis:  10 s x 3 times

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