The catalytic converter closest to the cylinder head can fail causing illumination of the Check Engine Light. Prompt repair of this problem is recommended because the catalyst material can be sucked into the engine and cause internal damage.Google+
Car Problem Reports
Nissan Sentra Check Engine Light Due to Failure of Catalytic Converter Closest to Cylinder Head
Nissan Sentra Problem
Exhaust & Emissions Affected: 2.5L 4 Cylinder
Average Mileage: 117,944 mi (81,500 mi - 142,500 mi)
Visitor, 2008 Nissan Sentra, 142,500 mi
Check engine light came on while driving--took to dealership and was told the catalytic converter needed replaced for around $950
The engine service soon light went on 3 days ago so I took my car to the dealer so they told me the catalytic must be replace.
Visitor, 2002 Nissan Sentra, 123,000 mi
Car runs fine but the "service engine soon" light came on that the repair shop said the codes showed a bad CC. We hope that's all that is wrong!
Visitor, 2005 Nissan Sentra, 119,500 mi
Had a fuel system cleaning done which set the check engine light off. Turned out to be the front catalytic converter for precisely the reason stated. Fixed through replacement.