P0421

The P0421 code in a BMW 5 Series F10/F11 (2010-2017) indicates an issue with the Warm-Up Catalyst Efficiency Below Threshold (Bank 1). This typically suggests that the catalytic converter is not functioning effectively or there is an issue with its related components.

The P0421 code indicates "Warm Up Catalyst Efficiency Below Threshold (Bank 1)" in a BMW 5 Series F10/F11 (2010-2017), suggesting a potential issue with the catalytic converter or related components.

The P0421 code indicates a warm-up catalyst efficiency issue in a BMW 5 Series G30/G31 (2017-2024). This typically points to problems with the catalytic converter's performance during the initial phase of engine operation.

The P0421 code indicates a problem with the warm-up catalyst efficiency for bank 1 in a 2017-2024 BMW 5 Series G30/G31. This often suggests issues with the catalytic converter or related components that affect emissions.