Toyota 25051-0H010 Exhaust Manifold Converter Sub-Assembly

The catalytic converter is an emission control device in the exhaust system that reduces pollutants. There are two types: oxidation catalyst, which reduces HC and CO levels, and three-way catalyst, which also decreases NOx. Checking the converter requires expensive equipment. During underbody servicing, inspect for leaks, corrosion, and damage. If any damage is found, replace the converter. To diagnose a restricted converter, use a vacuum gauge to assess the impact of a blocked exhaust on the intake vacuum. Connect the gauge to a vacuum source, warm the engine, and note the vacuum reading at idle and after opening the throttle. If the reading is more than one in-Hg lower after the fourth test, there may be a restriction. When replacing the converter, spray the nuts on the exhaust flange studs before removing them, and then proceed to remove the nuts and separate the converter from the exhaust system. The installation process is the reverse of the removal procedure.

Reinstall the remaining parts in the reverse order of removal, using new gaskets when connecting the exhaust pipes. Finally, run the engine and check for exhaust leaks.