P0420Medium Priority
Catalyst System Efficiency Below Threshold (Bank 1)
Category: Powertrain• Auxiliary Emission Controls
50 articles · 5 makes affected
Owner Data Insights
Most Effective Fixes for P0420
Based on 40 owner reports. Success rates show how often each fix resolved the issue.
67% success
9 reports
50% success
4 reports
33% success
9 reports
33% success
9 reports
33% success
9 reports
Start with the highest success rate fix when diagnosing P0420. If that doesn't resolve the issue, work down the list.
Frequently Appears With P0420
These codes often appear together in owner reports. Check these if you see P0420.
- P043012 reports
- P030010 reports
- P14496 reports
- P03026 reports
- P05056 reports
- P04576 reports
- P16006 reports
- P03013 reports
Based on analysis of 55 owner reports where multiple codes appeared together.
Owner Statistics for P0420
Based on 262 real owner discussions • 37 confirmed solutions
$675
Average Repair Cost
14%
Success Rate
262
Data Sources
About This Data
Statistics are aggregated from real owner discussions on Reddit, automotive forums, and YouTube comments. All data is anonymized and represents actual repair experiences reported by vehicle owners.
P0420 Issues by Vehicle
FORD
2015 F-150
2015 Ford F-150 Coolant Leak? Here's How to Fix It
100 sources
2020 F-150
2020 Ford F-150 P0420 Code: How To Diagnose & Fix It
10 sources
2016 F-150
2016 Ford F-150 P0420: Catalytic Converter Fix Guide
3 sources
2020 F-150
2020 Ford F-150 Battery Problems? Here's How to Fix It
427 sources
2016 F-150
2016 Ford F-150 BLIS Issues: How to Diagnose and Fix It
100 sources
2015 F-150
2015 F-150 Hard Start? How to Diagnose and Fix It
100 sources
2020 Mustang
2020 Ford Mustang Intake Leak? Causes, Symptoms & DIY Fix
133 sources
2016 F-150
Fixing Smoke Issues on Your 2016 Ford F-150
100 sources
2015 F-150
Humming Noise from Your 2015 F-150? Here's How to Fix It
100 sources
2020 Mustang
How to Fix an Exhaust Manifold Leak on Your 2020 Ford Mustang
263 sources
2020 F-150
Why is Your 2020 F-150 Making Cam Phaser Noise?
1.6K sources
2016 F-150
Fixing a Clicking Noise in Your 2016 Ford F-150's Front Differential
100 sources
2015 F-150
How to Fix an Oil Leak on Your 2015 Ford F-150 (Solenoid Focus)
100 sources
2016 F-150
2016 Ford F-150 Grinding Noise? Here's How to Fix It
100 sources
2015 F-150
Why is My 2015 F-150 Getting Bad Gas Mileage?
100 sources
2015 F-150
2015 Ford F-150 Check Engine Light? How to Fix Timing Chain Issues
100 sources
2020 F-150
Why Your 2020 F-150 Fuses Keep Blowing (And How to Fix It)
197 sources
2015 F-150
Why Is My 2015 Ford F-150 Making a Clicking Noise?
100 sources
2016 F-150
2016 F-150: What's Causing That Rattling Noise?
100 sources
2015 F-150
Why is Your 2015 Ford F-150 Vibrating? Find Out How to Fix It
100 sources
2015 F-150
Why is Your 2015 F-150 Making a Rattling Noise?
100 sources
2016 F-150
2016 Ford F-150 Misfire? Here's How to Diagnose & Fix It
100 sources
HONDA
2010 CR-V
2010 Honda CR-V Overheating? How to Fix Faulty Injector Clips
100 sources
2025 Civic
2025 Honda Civic Intake Leak? Here's How to Fix It
253 sources
2010 Civic
2010 Honda Civic Intake Manifold Vacuum Leak: DIY Fix Guide
89 sources
2025 CR-V
2025 Honda CR-V Rough Idle? Inspecting Wires for a Smooth Ride
100 sources
2010 CR-V
2010 Honda CR-V Vibrating? Here's How to Fix It
100 sources
2025 CR-V
2025 Honda CR-V Oil Leak? How to Diagnose and Fix Wiring Issues
100 sources
2010 CR-V
2010 Honda CR-V Oil Leak? Here's How to Check Your Injector Clips
100 sources
2025 CR-V
2025 Honda CR-V Clicking Noise: What's Wrong and How to Fix It
100 sources
2010 CR-V
Why Is My 2010 Honda CR-V Engine Knocking?
100 sources
2010 CR-V
2010 Honda CR-V Fuel Economy Dropping? How to Fix It
100 sources
2010 CR-V
2010 Honda CR-V Hard Start? A Simple Fix
100 sources
2025 CR-V
2025 Honda CR-V Hybrid Battery Problems? How to Diagnose & Fix
100 sources
2010 CR-V
Honda CR-V Stalling? Here's How to Fix It
100 sources
2020 Accord
2020 Honda Accord Transmission Issue? Try This Fuel System Fix
85 sources
2020 Accord
2020 Honda Accord Transmission Shudder? Here's How to Fix It
115 sources
2020 Accord
2020 Honda Accord: Why is Your Engine Rattling at Startup?
200 sources
2010 CR-V
2010 Honda CR-V Coolant Leak? Here's How to Fix It
100 sources
2020 Accord
How to Diagnose and Fix a Timing Chain Misfire in Your Honda Accord
246 sources
2020 Fit
How to Fix Battery Rattling Noise on Your 2020 Honda Fit
116 sources
2020 Accord
2020 Honda Accord Losing Coolant? Here's How to Fix It
121 sources
CHEVROLET
2010 Bolt
How to Fix a 2010 Chevrolet Bolt Misfire (Intake Leak)
100 sources
2010 Spark
2010 Chevrolet Spark Spark Plug Replacement: DIY Guide
330 sources
2010 Spark
2010 Chevrolet Spark Misfire? P0300 Code Troubleshooting
3 sources
2020 Corvette
Fixing 2020 Corvette Exhaust Manifold Issues: Rust & Overheating
1.3K sources