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Home >> Subaru >> 2007 >> Outback XT Limited, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DOTC) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P0171 System Too Lean (Bank 1) >> Diagnostic Method
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Diagnostic Method

Compare the diagnosed value (fsobd) with the threshold value, and if a condition of meeting the malfunction criteria below continues for 30 seconds or more, judge that there is a fault in the fuel system.

Judgment Value 

JUDGMENT VALUE

Malfunction Criteria Threshold Value
fsobd = (sglmd - tglmda) + faf + flat ≥ fsobdL 1
where,
sglmd = measured lambda fsobdL1 = lean side
See MAP 4 
tglmda = target lambda faf = main feedback compensation coefficient every 64 milliseconds
flaf = main feedback learning compensation coefficient
threshold value of fsobd

Map 4 Threshold value for fuel system malfunction criteria 

THRESHOLD VALUE

Amount of air (g (oz)/s) 0 (0) 2.3 (0.081) 4.7 (0.166) 7 (0.247) 9.4 (0.332) 11.7 (0.413) 14.1 (0.497)
fsobdL 1 (%) 40 40 36.9 32.0 27.0 26.5 26.5

Time Needed for Diagnosis:  10 seconds x 5 times

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

Judge as OK when the malfunction criteria below are met for 10 seconds or more.

Judgment Value 

JUDGMENT VALUE

Malfunction Criteria Threshold Value
fsobd = (sglmd - tglmda) + faf + flaf < 20%