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Home >> Subaru >> 2021 >> Legacy Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (2.5L) (Diagnostics) (2 Of 4) >> Diagnostic Procedure With Diagnostic Trouble Code (DTC) >> DTC P0420: Catalyst System Efficiency Below Threshold Bank 1 >> General Description >> Execution Condition
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Execution Condition

Secondary parameters Execution condition
Battery voltage 10.9 V or more
Barometric pressure 75.1kPa (563mmHg, 22.2 inHg) or more
Amount of intake air Less than 8.6g/s (0.3oz/s)
Accelerator pedal position While idling
Rear oxygen output voltage after fuel cut 0.15V or less
Estimated catalyst temperature 500°C (932°F) or more
Rear oxygen element impedance 185Ω or less
(Integrated intake air amount during fuel cut More than 18g (0.63oz)
Fuel shut-off function thereafter) Not in operation
A/F element impedance 75Ω or less