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Home >> Subaru >> 2023 >> Ascent Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (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 75.06 kPa (563.1 mmHg, 22.2 inHg) or more
Amount of intake air Less than 8.5 g/s (0.3 oz/s)
Accelerator pedal position While idling
Rear oxygen sensor output voltage after fuel cut 0.15 V or less
Estimated catalyst temperature 550°C (1022°F) or more
Estimated temperature of the rear oxygen sensor element 450°C (842°F) or more
(Integrated intake air amount during fuel cut More than 23.3 g/s (0.8 oz/s)
Fuel shut-off function thereafter) Not in operation
A/F element impedance 206 Ω or less