P0420 on HONDA FIT — Catalyst System Efficiency Below Threshold Bank 1

Q: "What does P0420 mean on a HONDA FIT?"

"P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 6 HONDA FIT owners have reported this to NHTSA."

Q: "What are the most common causes of P0420 on HONDA FIT?"

"Based on 6 NHTSA reports, the most commonly cited components are: Fuel/Propulsion System, Unknown Or Other,Fuel/Propulsion System, Engine,Fuel/Propulsion System. These percentages are based on the component field in owner complaints."

Q: "Is P0420 serious on my HONDA FIT?"

"Of 6 NHTSA reports for this code on HONDA FIT, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my HONDA FIT shows P0420?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What P0420 Means on Your HONDA FIT

P0420 is a diagnostic trouble code indicating: Catalyst System Efficiency Below Threshold Bank 1. This code relates to the emission controls system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

6 HONDA FIT owners have reported this issue to NHTSA across model years 2015-2018. Most reports come from the 2017, 2018 model years. The most commonly reported component is Fuel/Propulsion System (50.0% of reports).

Real HONDA FIT Owner Reports

Source: NHTSA Complaints Database

"Driving honda fit with approximately 65,000 miles. no prior issues with regular maintenance being done on it. all dashboard warning lights (check engine, tps, traction control sensor and steering wheel with exclamation mark) went on in the vehicle while driving on a city street to work."

— 2015 HONDA FIT owner · FUEL/PROPULSION SYSTEM · Filed 01/17/2020

"P0420 code on a 2017 Honda Fit. The vehicle only has 46,000 miles on it. It’s too early for me replace my catalytic converter. I know previous fit has the same problems but Honda said it was fixed. It’s too expensive to go to the dealership to get it diagnosed properly to look for the problem."

— 2017 HONDA FIT owner · UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM · Filed 02/20/2023

"My car started having issues with sputtering when accelerating. The check engine light came on and is throwing a P0420 code as well as a P219a code. These codes paired together appear to be related to faulty fuel injectors."

— 2017 HONDA FIT owner · FUEL/PROPULSION SYSTEM · Filed 02/01/2022

"P0420. Per Honda problem was fuel injector. 88000 miles. Seems too early to fail."

— 2017 HONDA FIT owner · FUEL/PROPULSION SYSTEM · Filed 01/03/2022

"At 74k miles my check engine light came on randomly. Took the car to a mechanic, who turned the light off and advised me to tighten the gas cap. A few weeks later the check engine light came back on. Auto zone said a spark plug needed replacement."

— 2018 HONDA FIT owner · ENGINE,FUEL/PROPULSION SYSTEM · Filed 10/03/2023

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

1

'15

3

'17

2

'18

Common Causes on HONDA FIT

Based on NHTSA complaint component analysis for this vehicle.

FUEL/PROPULSION SYSTEM 50%

UNKNOWN or OTHER,FUEL/PROPULSION SYSTEM 16.7%

ENGINE,FUEL/PROPULSION SYSTEM 16.7%

ENGINE and ENGINE COOLING 16.7%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P0420 mean on a HONDA FIT? ▾

P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 6 HONDA FIT owners have reported this to NHTSA.

What are the most common causes of P0420 on HONDA FIT? ▾

Based on 6 NHTSA reports, the most commonly cited components are: Fuel/Propulsion System, Unknown Or Other,Fuel/Propulsion System, Engine,Fuel/Propulsion System. These percentages are based on the component field in owner complaints.

Is P0420 serious on my HONDA FIT? ▾

Of 6 NHTSA reports for this code on HONDA FIT, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my HONDA FIT shows P0420? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.