Ford Edge P0420: Catalyst System Efficiency → Below Threshold → Bank 1

This page was created to assist you in troubleshooting the problem. Ford Edge P0420 trouble code. The Ford Edge P0420 definition, symptoms, causes, as well as possible solutions are covered. OBDII P0420 in the Edge is usually caused by an oxygen sensor problem, although there are other possible causes.

P0420 is a common code for Ford vehicles. This is the code that you get when you connect your Ford Edge to an OBDII scaner. 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

Ford Edge OBDII code P0420 Defined

P0420 It is an OBDII trouble code. Technically, the code stands for:

The Catalyst Systems Efficiency is Below the Threshold

At least two oxygen sensors are installed on your Edge, one just before the converter and another after it. They are responsible for measuring the emission levels entering and leaving the converter.

If the downstream and upstream oxygen sensors give similar readings, then the vehicle will soon turn on the service engine (P0420).

Your vehicle's software believes the catalytic convert is not doing its job.

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

Ford Edge Code P0420 Symptoms

If your oxygen sensors stop working properly, the Ford Edge's P0420 code will be displayed. The code is usually triggered by an oxygen sensor upstream (before 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- You may or not experience any problems depending on the extent of catalytic conversion blockage.
• 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 Ford Edge P0420 Code.

Similar: P0442 Ford Edge

Here are the Top 5 Reasons Why P0420 is in Ford Edge

P0420 can be caused by many factors in Edge. Below are some common reasons.

• 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 Edge’s exhaust. These can become blocked 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. It is more distant from the ECM which makes it even more volatile.
• Edge Timing– If your Edge 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.
• Motor Temp Sensor– If the computer doesn’t know what the engine temp is it’ll keep the fuel mixture rich. The O2 sensors will not see the mixture richly and could cause it to throw its sensor.

Possible Solutions for Ford Edge Code P0420

P0420 is often 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. Checking the exhaust for signs of leakage is a smart idea. 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. Below are some good guidelines to assist you in this task.

We wish you all the best in finding out why your Ford Edge is experiencing P0420. Please let us know if you find any errors or suggestions to improve this article. We are grateful.