P0431
Warm Up Catalyst Efficiency Below Threshold (Bank 2)
OBD-II
Catalytic converter
What it means
Close-coupled catalyst underperforming on bank 2.
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P0420
Catalyst System Efficiency Below Threshold (Bank 1)
Catalytic converterMedium
P0421
Warm Up Catalyst Efficiency Below Threshold (Bank 1)
Catalytic converterMedium
P0422
Main Catalyst Efficiency Below Threshold (Bank 1)
Catalytic converterMedium
P0430
Catalyst System Efficiency Below Threshold (Bank 2)
Catalytic converterMedium
P0432
Main Catalyst Efficiency Below Threshold (Bank 2)
Catalytic converterMedium
General reference only — what a code means can vary by make and model. Confirm with a qualified technician.