AutoCodes – Chevrolet – P0420 2017 Chevrolet Silverado

P0420 2017 Chevrolet Silverado Code - Catalyst System Low Efficiency Bank 1

Quick Answer

A 3-way catalyst controls emissions of hydrocarbons, Carbon Monoxide (CO), and Nitrogen Oxide (NOx). Common causes include Faulty Three-way Catalyst Converter Bank 1, Exhaust Tube, Intake Air Leaks. 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 Chevrolet Silverado indicates Catalyst System Low Efficiency Bank 1.
Common causes: Common causes include Faulty Three-way Catalyst Converter Bank 1, Exhaust Tube, Intake Air Leaks.
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 1,142

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 Jun 20, 2022

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 Chevrolet Silverado Description

A 3-way catalyst controls emissions of hydrocarbons, Carbon Monoxide (CO), and Nitrogen Oxide (NOx). The catalyst within the converter promotes a chemical reaction, which oxidizes the hydrocarbons and the CO that are present in the exhaust gas. This process converts the hydrocarbons and the CO into water vapor and carbon dioxide (CO2), and reduces the NOx, converting the NOx into nitrogen. The catalyst also stores oxygen. The Engine Control Module (ECM) monitors this process by using Heated Oxygen Sensors (HO2S) that are in the exhaust stream before and after the 3- way catalyst. The HO2S produces an output signal that the ECM uses to calculate the oxygen storage capacity of the catalyst. This indicates the ability of the catalyst to convert the exhaust emissions efficiently. The ECM monitors the efficiency of the catalyst by monitoring the HO2S during an off-idle, Decel Fuel Cut-Off (DFCO) event. When the catalyst is functioning properly, the post-catalyst HO2S response to the fuel conditions during the DFCO event is slow compared to the response of the pre-catalyst HO2S. When the post-HO2S response is near that of the pre-HO2S, the oxygen storage capability and efficiency of the catalyst may be degraded below an acceptable threshold. The Diagnostic Trouble Code (DTC) will be set when the ECM determines that the efficiency of the catalyst has degraded below a calibrated threshold.

OBDII Code P0420 2017 Chevrolet Silverado - Catalyst System Low Efficiency Bank 1 - AutoCodes.com — P0420 2017 Chevrolet Silverado Code - Catalyst System Low Efficiency Bank 1

What does this mean?

What are the Possible Causes of the DTC P0420 2017 Chevrolet Silverado?

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

How to Fix the DTC P0420 2017 Chevrolet Silverado?

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 control module has detected that the three-way catalytic converter is not working properly (it 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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0420 2017 Chevrolet Silverado 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 Chevrolet Silverado 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 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P0420 in a 2017 Chevrolet Silverado?

- Common symptoms include the check engine light illuminating, decreased fuel efficiency, and potential loss of engine power.

2. What does the OBDII code P0420 on a 2017 Chevrolet Silverado indicate?

- The code P0420 indicates a low efficiency in the catalytic converter of Bank 1, which may lead to increased emissions.

3. What are the possible causes of the Catalyst System Low Efficiency Bank 1 code in a 2017 Chevrolet Silverado?

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

4. Can driving with the P0420 code on a 2017 Chevrolet Silverado cause further damage?

- Continuing to drive with the P0420 code may lead to increased emissions, potential damage to the catalytic converter, and failure to pass emissions tests.

5. How can I diagnose the cause of the P0420 code in my 2017 Chevrolet Silverado?

- Diagnostic steps may involve checking the oxygen sensors, inspecting the catalytic converter for damage, and looking for exhaust leaks or engine issues.

6. Is it safe to continue driving my 2017 Chevrolet Silverado with the P0420 code?

- It is generally not recommended to drive for an extended period with the P0420 code as it can affect the vehicle's performance and lead to additional problems.

7. How much does it typically cost to repair the Catalyst System Low Efficiency Bank 1 code in a 2017 Chevrolet Silverado?

- Repair costs for the P0420 code can vary depending on the cause, but they may range from a few hundred to over a thousand dollars, especially if replacing the catalytic converter is necessary.

8. Can I reset the OBDII code P0420 on my 2017 Chevrolet Silverado without fixing the issue?

- While you can reset the code temporarily, the underlying problem will persist, and the check engine light is likely to come back on until the issue is resolved.

9. Are there any DIY repair tips for addressing the P0420 code in a 2017 Chevrolet Silverado?

- DIY tips may include checking for exhaust leaks, ensuring proper oxygen sensor function, and keeping up with regular maintenance to prevent issues that trigger the code.

10. How long does it take to repair the Catalyst System Low Efficiency Bank 1 code in a 2017 Chevrolet Silverado?

- The repair time can vary depending on the exact cause of the code, but it may take a few hours to a day for diagnostics and repairs to be completed by a professional mechanic.