HONDA Insight - Manual (Page 90)

90
Catalytic Converter Deterioration Detection / Replacement
The Insight uses 2 oxygen sensors to monitor the condition of the 3-way catalyst as required by OBD-II
and EU2000 regulations. However, the detection system is not able to directly monitor the condition of the
lean NOx catalyst.
If the ECM sets a code for a deteriorated catalyst, both catalysts have to be replaced. It must be
assumed that the same conditions that caused the 3--way catalyst to deteriorate also deteriorated the lean
NOx catalyst.
Exhaust Syste, Weight Saving Measures
The Insight's exhaust system incorporates several weight- and space-saving measures made possible by
the IMA engine's reduced size. For example, smaller-diameter, thinner gauge pipe is used, thereby saving
the weight that would be required for a larger engine. In addition, the system's smaller weight and the
elimination of the exhaust header (the header is now integral with the cylinder head) allowed it to be
constructed as a single unit, thus eliminating the additional weight of interconnecting exhaust flanges.