Question

What does error code P0420 mean on a Nissan?

If your Nissan shows a P0420 code, it usually means there is a problem with the catalytic converter on Bank 1.

If you see Error code P0420 while driving your Nissan, it usually means that it’s “Catalytic Converter Efficiency is Below Threshold (Bank 1)” or, in some of the brand’s newer models, “Three-Way Catalyst Malfunction. ” In simpler terms, this code means that the car’s computer has found that the catalytic converter is not working well enough to reduce harmful exhaust emissions.

Common reasons for this include:

• A worn-out catalytic converter
• Broken oxygen (O2) sensors
• Leaks in the exhaust system
• Incorrect air-fuel mixture
• Problems with the ignition or fuel system

Common symptoms you should keep an eye out for are:

• Illuminated check engine light
• Reduction in engine performance
• Emissions test fails
• Strong and/or unusual exhaust odors
• Increased fuel consumption