Infiniti Error Code P0420: How to Fix It

Q: Can I drive my Infiniti with P0420 code?

Yes, you can drive short distances, but the vehicle will fail emissions testing and may experience reduced fuel economy. Avoid extended driving as continued operation can damage other exhaust components.

Q: How much does it cost to fix P0420 on an Infiniti?

Costs range from $200-400 for oxygen sensor replacement to $1,200-2,500 for catalytic converter replacement, depending on your model and whether you use OEM or aftermarket parts.

Q: Why does P0420 keep coming back on my G35/G37?

Recurring P0420 codes often indicate underlying engine problems like misfires, oil burning, or fuel system issues that damage the catalytic converter. Address root causes before replacing the converter.

Q: Will seafoam or catalytic converter cleaner fix P0420?

Cleaners may help if the converter is mildly contaminated but won't fix a truly failed catalyst. They're worth trying as a first step but don't expect miracles on high-mileage vehicles.

Q: How long do Infiniti catalytic converters last?

Infiniti catalytic converters typically last 80,000-120,000 miles with proper maintenance. G35/G37 models may experience earlier failure due to high-performance engine design and heat stress.

Abstract

The Infiniti P0420 error code indicates that your catalytic converter on Bank 1 is not operating efficiently enough to meet emissions standards. This common issue on G35, G37, and Q50 models can be caused by a failing catalytic converter, faulty oxygen sensors, or engine performance problems that damage the catalyst over time.