Buick Encore persistent engine light indicating catalytic converter failure after replacement and removal of second converter on Buick Encore

Some Buick Encore owners report experiencing persistent Check Engine lights following catalytic converter replacement, which may be attributed to sensor malfunctions, installation errors, or back pressure issues. These owners emphasize the importance of proper installation procedures to prevent future errors and ongoing Check Engine light problems. Additionally, they highlight the need to check the functionality of oxygen sensors, as malfunctioning sensors can falsely indicate converter inefficiency. Many owners find it helpful to use an OBD-II scanner to identify diagnostic trouble codes like P0420 or P0430, which can shed light on efficiency issues with the converter. Symptoms reported by owners of failing converters include reduced engine performance, poor gas mileage, and illuminated warning lights. Furthermore, some Buick Encore owners note that cooling system concerns, such as coolant leaks and overheating, can also affect engine performance and trigger warning lights, underscoring the need for comprehensive diagnostics to resolve these issues.