2018 Rogue SV - P0420 Code and Check Engine Light

ClearTheCode guidance (Nissan · Diagnostics & codes)

Summary: For 2018 Rogue SV - P0420 Code and Check Engine Light, work through these steps on your 2016+ vehicle:

1. Confirm the symptom — note when it happens (cold start, highway, after fuel fill, etc.).
2. Scan codes — save all pending/stored DTCs; don't clear until you've recorded them.
3. Check TSBs & recalls — look up your VIN for open campaigns and known fixes.
4. Inspect the obvious — related fuses, connectors, fluid level, and recent repairs.
5. Test the common fix — follow model-specific service procedures; one change at a time.
6. Escalate if needed — burning smell, no brakes, overheating, or stalling in traffic → shop visit.

Owner reported: My 2018 Nissan Rogue SV recently threw a Check Engine Light. I used my OBD-II scanner and it pulled a P0420 code, which points to "Catalyst System Efficiency Below Threshold (Bank 1)".

The car seems to be running okay, no noticeable loss of power or strange noises. Fuel economy might be slightly worse, but it's hard to tell for sure.

What are the common causes for this code on a Rogue of this ye…

This is educational guidance, not a substitute for hands-on diagnosis.