AutoCodes – Honda – P0420 2017 Honda CR-V

P0420 2017 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 2017 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 459

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 2017 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 2017 Honda CR-V - Catalyst System Efficiency Below Threshold - AutoCodes.com — P0420 2017 Honda CR-V Code - Catalyst System Efficiency Below Threshold

What does this mean?

What are the Possible Causes of the DTC P0420 2017 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 2017 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 2017 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 2017 Honda CR-V code?

Need more information on how to fix the P0420 2017 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 2017 Honda CR-V Code

1. What are the common symptoms of a P0420 code in a 2017 Honda CR-V?

- Common symptoms include the check engine light coming on, reduced fuel efficiency, and potential lack of power or acceleration.

2. What are the possible causes of a P0420 code in a 2017 Honda CR-V?

- Possible causes include a faulty catalytic converter, oxygen sensor issues, exhaust leaks, engine misfires, or a faulty fuel injector.

3. Can a P0420 code in a 2017 Honda CR-V be caused by a bad oxygen sensor?

- Yes, a faulty oxygen sensor can cause a P0420 code by providing inaccurate data to the engine control module, leading to incorrect fuel-air mixture adjustments.

4. How can I diagnose the underlying issue causing a P0420 code in my 2017 Honda CR-V?

- Diagnosing the issue may involve checking the oxygen sensors, inspecting the catalytic converter, looking for exhaust leaks, and ensuring proper engine performance.

5. Is it safe to continue driving my 2017 Honda CR-V with a P0420 code?

- While it may be safe to drive with the code in the short term, it is recommended to address the underlying issue promptly to prevent potential damage to the catalytic converter or other components.

6. Can using low-quality fuel trigger a P0420 code in a 2017 Honda CR-V?

- Yes, using low-quality fuel or fuel with a high sulfur content can contribute to the formation of deposits in the catalytic converter, potentially triggering a P0420 code.

7. How much does it typically cost to repair a P0420 code in a 2017 Honda CR-V?

- The cost of repairs for a P0420 code can vary depending on the underlying issue, but it may range from a few hundred to over a thousand dollars, especially if the catalytic converter needs replacement.

8. Can a P0420 code in a 2017 Honda CR-V be temporarily cleared by resetting the check engine light?

- Resetting the check engine light may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear after the vehicle goes through its drive cycle.

9. Are there any DIY repair tips for addressing a P0420 code in a 2017 Honda CR-V?

- DIY tips may include checking for exhaust leaks, ensuring proper engine maintenance, using fuel system cleaners, and monitoring the oxygen sensor readings.

10. How long can I drive my 2017 Honda CR-V with a P0420 code before it causes significant damage?

- It is advisable to address the P0420 code promptly to prevent potential damage to the catalytic converter, which can lead to decreased engine performance and increased emissions over time.