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: 125,088 mi (59,645 mi - 185,331 mi)
Visitor, 2008 Nissan Sentra, 145,350 mi
I am about to go on a 2,000 mile road trip and this is come on. I passed emissions today but gave the the Catalytic Converter error message. I am getting checked out tomorrow by the dealership and I hope I do not have to replace anything.
Visitor, 2006 Nissan Sentra, 59,645 mi
Code p 420 service engine soon
Visitor, 2008 Nissan Sentra, 114,500 mi
Intermittent check engine light. Dealer and alt repair shop advised bad cat. Took to a third shop for full breakdown of exhaust system and found cat split at the welds. Mechanic quote, "Robot did not have its coffee that day". Replaced at cost of 983.00. Core sent back to Nissan or would be charged another 140.00.
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.