Easy step by step repair guide on how to replace a catalytic converter (P0420
-P0421 below efficiency threshold) though appearances will vary, the process is
similar for most vehicles.
Difficulty Scale: 5 of 10
Tools and Supplies Needed
Replacement catalytic converter
Protective eye wear and gloves
Begin with the car safely supported in the air with jack stands enough to work
on the exhaust system.
Step 1 - Exhaust systems tend to rust the mounting
bolts of the system. To help dis-assembly spray the bolts on the manifold and other
connections with penetrating lube to help loosen.