Tips in clearing P0420 obd2 codes
P0420 code denotes a malfunction in the catalytic converter (cat) as designated by the post (downstream) oxygen sensor. As in many cases like this, it is a good idea to measure the voltage oscillation of the oxygen sensors between the front and the back oxygen sensors. At the front (usually located at the exhaust manifold), it should oscillate about 0.1 to 0.9 volt at
the signal wire whereas the back ones should oscillate less say around 0.3 volt to 0.6 volt. Depending on the models, if the oscillation is greater than this, it indicates a CAT failure.
Tips:
Most cat is guaranteed up to 8 years or 80,000 km so check with your dealer and service bulletins if your vehicle is covered.
If your vehicle is not covered, you can buy an after market cat with at least 50% savings but make sure it follows the manufacturer’s efficiency guidelines. To confirm this, get an exhaust analysis reading before and after the catalytic converter is installed.
On some imported models, there could be no voltage oscillations at the post oxygen sensors, to be safe contact ATS for the right readings.
Make sure the engine computer (ecm) is fully cleared of the code after installing the new cat. If not, the P0420 code can return and give you a false code.
Thanks!
