AutoCodes – Chevrolet – P0420 2016 Chevrolet Silverado

P0420 2016 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 2016 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 919

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 2016 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 2016 Chevrolet Silverado - Catalyst System Low Efficiency Bank 1 - AutoCodes.com — P0420 2016 Chevrolet Silverado Code - Catalyst System Low Efficiency Bank 1

What does this mean?

What are the Possible Causes of the DTC P0420 2016 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 2016 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 2016 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.

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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 2016 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P0420 on a 2016 Chevrolet Silverado?

- Common symptoms include decreased fuel efficiency, rough idling, and the illumination of the check engine light.

2. What does the OBDII code P0420 "Catalyst System Low Efficiency Bank 1" mean for a 2016 Chevrolet Silverado?

- This code indicates that the catalytic converter is not functioning at its optimal efficiency level on bank 1 of the engine.

3. What are the potential causes of OBDII code P0420 on a 2016 Chevrolet Silverado?

- Possible causes include a faulty catalytic converter, oxygen sensor issues, exhaust leaks, engine misfires, or a malfunctioning mass airflow sensor.

4. Can a bad O2 sensor cause code P0420 on a 2016 Chevrolet Silverado?

- Yes, a malfunctioning oxygen sensor can contribute to triggering code P0420 as it may provide incorrect data to the engine control module, leading to inefficient catalytic converter operation.

5. How can I diagnose the issue related to OBDII code P0420 on my 2016 Chevrolet Silverado?

- Diagnosis typically involves checking the oxygen sensors, inspecting for exhaust leaks, performing a visual inspection of the catalytic converter, and analyzing data from the vehicle's onboard diagnostic system.

6. Is it safe to continue driving my 2016 Chevrolet Silverado with OBDII code P0420?

- It is generally not recommended to drive for an extended period with code P0420, as it can lead to increased emissions, potential damage to the catalytic converter, and reduced engine performance.

7. How much does it cost to repair OBDII code P0420 on a 2016 Chevrolet Silverado?

- The cost of repairing code P0420 can vary depending on the specific issue, but it may involve replacing the catalytic converter, oxygen sensors, or other components, costing anywhere from a few hundred to over a thousand dollars.

8. Can I reset the check engine light after fixing the issue causing code P0420 on my 2016 Chevrolet Silverado?

- Yes, once the underlying problem triggering code P0420 has been addressed and repaired, the check engine light can be reset using an OBDII scanner to clear the error code.

9. Are there any DIY repair tips for addressing OBDII code P0420 on a 2016 Chevrolet Silverado?

- While some basic checks like inspecting for exhaust leaks or replacing oxygen sensors can be DIY tasks, diagnosing and repairing the root cause of code P0420 may require professional expertise due to the complexity of the catalytic converter system.

10. How often does OBDII code P0420 reoccur after it has been repaired on a 2016 Chevrolet Silverado?

- If the underlying issue causing code P0420 is not fully resolved, or if there are related problems within the emissions system, the code may reoccur even after initial repairs. It is essential to ensure a thorough diagnosis and complete repair to prevent recurrence.