Catalytic Converters Blog

One-wire and two-wire “unheated” type oxygen sensors should be check or replaced ever 30,000 to 50,000 miles. These sensors rely solely on hot exhaust gas to heat up to operating temperature, and are designed to allow a large volume of exhaust gas to make contact with the active ceramic element. These sensors are exposed to contamination, especially the “wide-slot” varieties found on Chrysler, Ford and General Motors vehicles.

“Heated” type oxygen sensors have a built-in heater which heats the sensors. Much less exhaust gas needs to contact the ceramic element, making these sensors less prone to contamination.

“Heated” type sensors can also be located further downstream, (closer to the catalytic converter), which increases their life expectancy. “Heated” type oxygen sensors should be checked or replaced every 60,000 to 100,000 miles.

Catalytic Converters don’t commit suicide!!!

Something fails in the engine management system to damage them or keep them from doing their job. Also, make sure to de-carbonize all engines over 50,000 miles.

PO 420 Code…What do I do first?

Things to check related to PO 420 Codes:

• Check Engine for other codes and Technical Service Bulletins (TSB’s)
• Engines with excess of 50,000 miles should be de-carbonized !!!!
• Check EGR vale for proper operation. Make sure EGR ports are clean and open.
• Check for engine mis-fires. Coil Paks – Spark Plugs – Plug Wires
• Check fuel delivery system. Rich mixture – dirty injectors – pressure regulator and EVAP issues.
• Check for intake and exhaust leaks. Air – Vacuum – Fluid
• Check or replace ALL Oxygen Sensors
• Check engine thermostat for proper operation.
• Check & Clean MASS Air Flow Sensor.
• Check ALL Coolant & Engine Temperature

Check for obvious signs of road damage to the converter and signs of excessive heat (blue and purple coloring of the converter or heat shield). Check for proper air flow out of the tailpipe. Check for excessive carbon in the tail pipe.