What does code P0420 mean?

Code P0420 means catalyst system efficiency below threshold, which indicates your catalytic converter is not cleaning the exhaust as well as it should on bank 1. While a failing catalytic converter is the most common cause, P0420 can also be triggered by a bad oxygen sensor, an exhaust leak, engine misfires, or even the wrong fuel mixture. This is why replacing the converter without proper testing is a costly mistake, since the real problem may be a far cheaper sensor or leak. A computerized diagnostic checks the oxygen sensor readings, looks for exhaust leaks, and confirms whether the converter itself has actually failed. At Motoro Cars in Miami, our ASE-certified, AAA-approved technicians diagnose P0420 accurately before recommending any repair. Call Wynwood at (786) 634-2002 or Doral at (786) 633-3220 to find out the true cause and avoid replacing parts you do not need.