AutoCodes – Honda – P0420 2020 Honda CR-V

P0420 2020 Honda CR-V Code - Catalyst System Efficiency Below Threshold

Quick Answer

The Three-Way Catalytic Converter (TWC) converts Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx) in the exhaust gas to water vapor, Carbon Dioxide (CO 2), and Dinitrogen (N 2). Common causes include Faulty Three-Way Catalytic Converter (TWC), Faulty Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)), Secondary Heated Oxygen Sensor 2 harness is open or shorted. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0420 2020 Honda CR-V indicates Catalyst System Efficiency Below Threshold.
Common causes: Common causes include Faulty Three-Way Catalytic Converter (TWC), Faulty Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)), Secondary Heated Oxygen Sensor 2 harness is open or shorted.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 465

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 18, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0420 2020 Honda CR-V Description

The Three-Way Catalytic Converter (TWC) converts Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx) in the exhaust gas to water vapor, Carbon Dioxide (CO 2), and Dinitrogen (N 2). The Powertrain Control Module (PCM) fluctuates the air/fuel ratio temporarily to detect the performance of the TWC and measures the degree of fluctuation in the secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) output. If the accumulated value for a set time is too great, deterioration of the performance of the catalyst is detected, and the PCM detects a malfunction and stores a Diagnostic Trouble Code (DTC).

OBDII Code P0420 2020 Honda CR-V - Catalyst System Efficiency Below Threshold - AutoCodes.com — P0420 2020 Honda CR-V Code - Catalyst System Efficiency Below Threshold

What does this mean?

What are the Possible Causes of the DTC P0420 2020 Honda CR-V?

Faulty Three-Way Catalytic Converter (TWC)
Faulty Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2))
Secondary Heated Oxygen Sensor 2 harness is open or shorted
Secondary Heated Oxygen Sensor 2 circuit poor electrical connection

How to Fix the DTC P0420 2020 Honda CR-V?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

As the code description implies, the P0420 code means that the vehicle's Powertrain Control Module (PCM) has detected that the Three-way Catalyst Converter is not working properly (it is not as efficient as the factory expects). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases, the Three-way Catalyst Converter needs to be replaced to resolve the problem. If the P0420 code is combined with other codes, try addressing the other codes first.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0420 2020 Honda CR-V code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0420 2020 Honda CR-V code?

Need more information on how to fix the P0420 2020 Honda CR-V code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0420 2020 Honda CR-V Code

1. What does the OBDII code P0420 mean on my 2020 Honda CR-V?

The P0420 code indicates that the catalyst system efficiency in your Honda CR-V is below the threshold set by the manufacturer.

2. What are the common symptoms of a P0420 code on a 2020 Honda CR-V?

Common symptoms include decreased fuel efficiency, the Check Engine Light illuminating, and possible loss of engine power.

3. What are the possible causes of a P0420 code on a 2020 Honda CR-V?

Potential causes include a faulty catalytic converter, oxygen sensor issues, exhaust leaks, or engine misfires.

4. Can I continue driving my 2020 Honda CR-V with a P0420 code?

It is generally safe to drive the vehicle with a P0420 code, but it is recommended to have it diagnosed and repaired promptly to prevent further damage.

5. How do I diagnose a P0420 code on my 2020 Honda CR-V?

Diagnosis typically involves checking the oxygen sensors, inspecting the catalytic converter, and looking for any exhaust leaks or misfires.

6. What are some repair tips for fixing a P0420 code on a 2020 Honda CR-V?

Repair tips may include replacing the catalytic converter, repairing exhaust leaks, replacing faulty oxygen sensors, or addressing any engine misfires.

7. Can a P0420 code on a 2020 Honda CR-V be triggered by a loose gas cap?

While a loose gas cap can trigger some codes, the P0420 code specifically relates to catalytic converter efficiency and is not typically caused by a loose gas cap.

8. How much does it cost to repair a P0420 code on a 2020 Honda CR-V?

Repair costs for a P0420 code can vary depending on the underlying issue, but it may range from a few hundred to a few thousand dollars, depending on the extent of repairs needed.

9. Are there any recalls or technical service bulletins related to the P0420 code on a 2020 Honda CR-V?

It's recommended to check with your local Honda dealership or visit the National Highway Traffic Safety Administration (NHTSA) website to see if there are any relevant recalls or bulletins.

10. How can I prevent a P0420 code from appearing on my 2020 Honda CR-V in the future?

Regular maintenance, such as timely oil changes, using quality fuel, and addressing any engine performance issues promptly, can help prevent the recurrence of a P0420 code.