Posts Tagged: O2 sensor diagnosis

Why Oxygen Sensors Rarely Cause P0420 or P0430 Codes

Understanding the Relationship Between the O2 Sensors and a P0420 or P0430 Code Quick summary An oxygen sensor rarely causes a P0420 or P0430. That’s because the engine computer needs a working oxygen sensor to even test catalytic converter efficiency. A P0420 or P0430 means the converter is no longer storing oxygen properly, or there are underlying issues like exhaust leaks, fuel trim problems, or engine conditions that slowly killed the converter. Understanding how the computer uses the oxygen sensor data makes diagnosing P0420 and P0430 far more accurate and … Read More