P0420 NISSAN - Catalyst System Efficiency Below Threshold Bank 1

Repair Importance Level: 2/3
Repair Difficulty Level: 2/3  What does this mean?

P0420 Nissan Possible Causes

  • Faulty Three-way Catalyst Converter Bank 1
  • Exhaust Tube
  • Intake Air Leaks
  • Faulty Oxygen (O2) Sensor
  • Faulty Fuel injector(s)
  • Leaking Fuel Injector (s)
  • Faulty Spark plugs
  • Improper Ignition Timing
  • Faulty Engine Control Module (ECM)
  • Dirty Air Filter

P0420 Nissan Tech Notes

As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.

Very common problem with Nissan vehicles. There are Nissan factory service bulletins for the following Nissan models:

2000 Nissan Maxima
2001 Nissan Maxima
2000-2001 Nissan Maxima Factory Service Bulletin OBDII Code P0420

2001 Nissan Frontier
2001 Nissan Xterra
2001 Nissan Frontier-Xterra Factory Service Bulletin OBDII Code P0420

2004 Nissan Altima
2005 Nissan Altima
2004-2005 Nissan Altima Factory Service Bulletin OBDII Code P0420

2004 Nissan Altima
2005 Nissan Altima
2006 Nissan Altima
2004-2006 Nissan Altima Factory Service Bulletin OBDII Code P0420

2005 Nissan Frontier
2006 Nissan Frontier
2005-2006 Nissan Frontier Factory Service Bulletin OBDII Code P0420

Cost of diagnosing the P0420 Nissan code

    Labor: 1.0

    The cost of diagnosing the P0420 Nissan code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.

When is the code detected?

- Three way catalytic converter Bank 1 does not operate properly.
- Three way catalyst converter Bank 1 does not have enough oxygen storage capacity.

P0420 Nissan Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0420 Nissan Meaning

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).

A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.

When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.

OBDII Code P0420 Nissan - Catalyst System Efficiency Below Threshold Bank 1 - Engine-Codes.com

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