P0421

The vehicle is displaying a P0421 trouble code, indicating the catalytic converter's efficiency is below the required threshold for Bank 1 in a Volkswagen Passat B8 (2015-2022).

The P0421 code indicates that the engine control module (ECM) has detected an issue with the warm-up catalytic converter efficiency on a 2015-2022 Volkswagen Passat B8. This can lead to increased emissions and potentially affect engine performance.

The P0421 code on a 2015-2022 Volkswagen Passat B8 indicates an issue with the warm-up catalyst efficiency for bank 1. This typically points to problems with the catalytic converter, oxygen sensors, or exhaust system.

The P0421 code indicates that the engine control module (ECM) has detected an issue with the warm-up catalyst efficiency for Bank 1 in a 2015-2022 Volkswagen Passat B8. This typically relates to problems with the catalytic converter or oxygen sensors.

The P0421 code indicates "Warm Up Catalyst Efficiency Below Threshold (Bank 1)" in a 2015-2022 Volkswagen Passat B8. This typically suggests that the catalytic converter is not operating efficiently when the engine is warm.