Catalytic Converters: Maintenance
The only maintenance required on the catalytic converter is to check tightness of flange bolts and efficiency of converter every 15, 000 miles. The efficiency of the catalytic converter can be checked by measuring CO% level at plug in front of converter and at tailpipe, and comparing the two readings. If CO% level readings remain about the same on both sides of the converter, the converter is defective and should be replaced as an assembly.