Compare OBD codes and concepts

Compare catalyst codes, oxygen-sensor positions, engine banks and OBD reference scope. Use each comparison’s scoped reference wording and vehicle service information to interpret the definitions.

• P0420 vs P0430

  P0420 and P0430 have the same catalyst-efficiency definition, with a different bank. Compare the scoped reference wording before using either code.

• Upstream vs downstream O2 sensor

  For exhaust oxygen sensors, Sensor 1 is upstream, closest to the engine; Sensor 2 is downstream, after the catalyst. Confirm the exact sensor layout in the vehicle’s service information.

• Bank 1 vs Bank 2

  Bank 1 is the side containing cylinder 1. Bank 2 is the other side on V or flat engines; inline engines have only Bank 1.

• OBD1 vs OBD2: reference scope

  OBD Lens publishes generic OBD2 and manufacturer reference families. Use the reference namespace and vehicle profile to establish the scope of a definition.

Reference-family membership is not proof that a code applies to every listed ECU or vehicle. Runtime-ready definitions are not physical-vehicle validation. Unavailable readings must not be treated as zero. App and hardware sale availability must be checked separately.