What Will Render a Catalytic Converter Inefficient?
Poor vehicle maintenance is a major contributor to the
creation of conditions that eventually lead to converter
inefficiency.

Poor vehicle maintenance is a major contributor to the
creation of conditions that eventually lead to converter
inefficiency.

It is important to remember that if the “Check Engine Light” illuminates and you read a code of PO420, 421, 430 or 431 this does not necessarily mean the Catalytic Converter is bad! All the code says is either Converter operating below efficency or Converter operating under threshold. Nowhere does the code say that the converter is bad.
The vehicle may very well need a Catalytic Converter but to determine this you should perform proper engine diagnostics. The reading of a simple code is NOT performing diagnostics. The following material should give you a better understanding of what proper diagnostics consist of and how they should be performed. If after reading the material below you still have questions please give us a call, 817-551-7700, and we will do all we can to help you solve the problem.



Following is a complete Diagnostic Manual in helping you diagnose and troubleshoot problems with a vehicles emission system and the possible replacement of emission parts including the catalytic converter.

One of the most important diagnostic changes to come out of On-Board Diagnostics Generation II (OBDII) is
that of Misfire Detection.


The following Toyota factory bulletin refers to codes P0171 and P0174, lean conditions on either or both banks, but this raises cause for concern when diagnosing catalytic converter codes as well. This bulletin is acknowledging there may be a problem with the Intake Air Control Valves on 2004 Camry, Sienna and Solara vehicles with 3.3L (3MZ-FE) engines.

