What does code P0420 versus P0430 mean?

Codes P0420 and P0430 both mean catalyst system efficiency is below threshold, with the only difference being which side of the engine they refer to: P0420 is bank 1 and P0430 is bank 2 on V-shaped engines. Both indicate that a catalytic converter is not cleaning the exhaust as effectively as it should. However, neither code automatically means the converter has failed, because a bad oxygen sensor, an exhaust leak, or an engine misfire can produce the same reading. This is why replacing a converter without proper testing is a costly mistake. A computerized diagnostic checks oxygen sensor data and looks for leaks before condemning the converter. At Motoro Cars in Miami, our ASE-certified, AAA-approved technicians diagnose P0420 and P0430 accurately. Call Wynwood at (786) 634-2002 or Doral at (786) 633-3220 to find the true cause before spending on an expensive part.