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Home >> Subaru >> 2009 >> Forester XT >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Diagnostic Trouble Code (DTC) Detecting Criteria (H4DOTC) >> Diagnostic Trouble Code (DTC) Detecting Criteria >> DTC P0139 O2 Sensor Circuit Slow Response (Bank 1 Sensor 2) >> Enable Condition
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Enable Condition

Rich → lean diagnosis response

ENABLE CONDITION

Secondary Parameters Enable Conditions
Battery voltage ≥ 10.9 V
A/F main feedback control condition Completed
Deceleration fuel cut time is 5000 ms or more. Experienced
After fuel cut ≥ 2000 ms
Current calculation time of the rear oxygen sensor heater ≥ 60000 ms
Current continuation time of the rear oxygen sensor heater ≥ 30000 ms
Estimated catalyst temperature ≥ 400 °C (752 °F)
Number of deceleration fuel cut ≥ 1 time(s)


Lean → rich response diagnosis

ENABLE CONDITION

Secondary Parameters Enable Conditions
Battery voltage ≥ 10.9 V
A/F main feedback control condition Completed
Deceleration fuel cut time is 6000 ms or more. Experienced
After fuel cut ≥ 2000 ms
Current calculation time of the rear oxygen sensor heater ≥ 0 ms
Current continuation time of the rear oxygen sensor heater ≥ 0 ms
Estimated catalyst temperature ≥ 0 °C (32 °F)
Number of deceleration fuel cut ≥ 1 time(s)