Diagnostics and Meaning for the P0420 Chevy Traverse OBDII Code

P0420 Chevy Traverse

This page will help you to troubleshoot your problem. Chevy Traverse P0420 trouble code. The Chevy Traverse P0420 definition, symptoms, causes, as well as possible solutions is covered. OBDII P0420 in the Traverse is usually caused by a defective oxygen sensor. However, there are other possible causes.

P0420 is a common code for Chevy vehicles. The code refers to a number you receive when your Chevy Traverse is plugged into an OBDII scanner. It doesn’t matter which model you have, this OBDII code has the same meaning for all of them.


P0420: Catalyst System Efficiency below Threshold


Índice de Contenido
  1. Chevy Traverse P0420 OBDII Code Defined
  2. Chevy Traverse P0420 Code Symptoms
  3. Here are the Top 5 Reasons P0420 is in Chevy Traverse
  4. Possible Solutions for Chevy Traverse Code P0420

Chevy Traverse P0420 OBDII Code Defined

ChevyP0420 Code Symptoms

P0420 This is an OBDII Trouble Code. This code is technically:

The Catalyst Systems Efficiency is Below the Threshold

There are at least two oxygen sensors on the Traverse. One is before the catalytic converter, and one after. They are responsible for measuring the emission levels entering and leaving the converter.

The vehicle will light the service engine when the oxygen sensor readings show identical readings (P0420).

Software in your car believes that the catalytic conversion isn't doing its job.

If your vehicle has the P0420 code, it won’t pass emissions so please be aware of that.

Chevy Traverse P0420 Code Symptoms

ChevyP0420 OBDII Trouble Code

If your oxygen sensor isn't working correctly, the P0420 code on a Chevy Traverse may be displayed. In most cases, the code is triggered from the oxygen sensor above the converter.

There aren’t usually any drivability issues associated with P0420. The first indication that something is amiss is usually the soon-light coming on in the service engine.

These are some of the symptoms you should look out for if your code is P0420.

  • Mileage- It is possible for your catalytic converter to become clogged.
  • The loss of power– It is a really strange feeling to drive a vehicle with a catalytic converter that is going out. Typically, they’ll idle ok and drive normal under a light load. Whenever the engine is put under a heavy load it’ll feel like it is running out of gas. It’s very similar to the symptoms of a bad fuel filter.
  • Service Engine Light– Often, this is the only symptom of the Chevy Traverse P0420 code.


Here are the Top 5 Reasons P0420 is in Chevy Traverse

OBD2 Code P0420 Chevy

You can have the Traverse's P0420 code problem for many reasons. These are some of the more common.

  • Oxygen Sensor– The P0420 codes is thrown when the oxygen sensors on both sides of the exhaust have very similar readings. An oxygen sensor that is defective can give false readings and cause the code to be triggered. If the engine does not exhibit any of the decreased performance associated with a bad catalytic converter, it very well may be the oxygen sensor (if you haven’t noticed the performance loss yet).
  • Catalytic Converter– A catalytic converter is responsible for scrubbing out as much pollution as possible from the Traverse’s exhaust. They can get clogged over time. Modern catalytic converters should last for the lifetime of most cars, but if they have become clogged, there could be an underlying issue.
  • O2 Sensor Connectivity– Over time, the oxygen sensor wiring can go bad. This is because it is directly next to hot exhaust. Because it's so far away from the ECM, downstream oxygen sensor wiring can be volatile (more travel).
  • Timing of Traverse– If your Traverse is misfiring or the exhaust timing is off, this can affect the gasses that are actually going to the O2 sensors enough to cause the P0420 code to register.
  • Exhaust Leak– If there’s a noticeable exhaust leak coming from the vehicle it can change what the O2 sensors register enough to throw the P0420 code.
  • Engine Temperature Sensor– If the computer doesn’t know what the engine temp is it’ll keep the fuel mixture rich. If the fuel mixture becomes too rich it will cause the O2 sensor to see an exhaust that is out of normal range. This could result in the sensor being thrown.


Possible Solutions for Chevy Traverse Code P0420

P0420 can often be caused by the oxygen sensor. Specifically it’ll usually be the O2 sensor(s) on the upstream side of the catalytic converter.

But, don’t be surprised if it’s not. You should check your exhaust first for any leaks. It should be possible to detect an exhaust leak underneath the vehicle.

Unless you have an exhaust leak, you’ll probably need to test the O2 sensors and/or catalytic converters. These are some great guides that will help you.


You will be able to solve the problem with your Chevy Traverse by using these tips. Please let us know if you find any errors or suggestions to improve this article. We are grateful.

Other Common Traverse Codes:  P0171 Chevy Traverse, Chevy Traverse P0700 Code

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