4 documented codes across 38 real diagnostics.
Catalyst efficiency below threshold. P0420 is the second most common code overall and is very often a lambda sensor rather than a dead catalyst.
Ranked by how often we actually see them
- P0420, Catalyst system efficiency below threshold, bank 1
- P042F, not individually documented
- P0426, Catalyst temperature sensor circuit range/performance, bank 1
- P0430, Catalyst system efficiency below threshold, bank 2