A catalytic converter is an emission control device in the exhaust system that reduces certain pollutants in the exhaust gas stream, with two types, First, there are oxidation converters, which are basically reduction converters turned around and used in the opposite way. Oxidation converters use a ceramic honeycomb substrate plated with platinum and palladium so as to bring about the following chemical reaction; oxidation of hydrocarbon substances and carbon monoxide through introduction of oxygen into the exhaust flow; the resulting by-products being water vapor and carbon dioxide. Reduction converters on the other hand are plated with platinum and rhodium they reduce oxides of nitrogen by robing the oxygen leaving nitrogen and carbon dioxide. The catalytic converters that cut all the three pollutants are called three way catalytic converters and all models discussed below are fitted with these. The catalytic converter is set in the exhaust pipe after the joining of the two outlet pipes of the exhaust manifolds. If the belief is that there is a bad converter, then the best place for diagnosing this are a dealer or an authorised emission inspection facility since the required diagnostic tools are costly. When you are in the process of servicing of the underbody parts, check whether the converter assembly have signs of leakage, corrosion, dents, and other signs of damages around the welds and bolts that are used to hold the converter assembly to the exhaust system. The converters are fairly indestructible but can be blocked; a vacuum gauge can then be used to check the exhaust system for restrictions. To replace this unit one has to turn the ignition key off, securely jack up the vehicle and carry out the following procedures, disconnect the electrical connector from the downstream
Oxygen Sensor and withdraw the sensor. Next, unbolt the retaining nuts on the front and rear catalyst mounting flanges, and the procedures of installation are opposite to the procedures of removal, when replacement of the whole set of the rusty and damaged bolts and nuts is required, and the bolts must be tightened with the permitted torque.