P0420 on CHEVROLET MALIBU — Catalyst System Efficiency Below Threshold Bank 1

Q: "What does P0420 mean on a CHEVROLET MALIBU?"

"P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 3 CHEVROLET MALIBU owners have reported this to NHTSA."

Q: "What are the most common causes of P0420 on CHEVROLET MALIBU?"

"Based on 3 NHTSA reports, the most commonly cited components are: Engine,Fuel/Propulsion System, Power Train,Engine. These percentages are based on the component field in owner complaints."

Q: "Is P0420 serious on my CHEVROLET MALIBU?"

"Of 3 NHTSA reports for this code on CHEVROLET MALIBU, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my CHEVROLET MALIBU 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 CHEVROLET MALIBU

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.

3 CHEVROLET MALIBU owners have reported this issue to NHTSA across model years 2009-2014. Most reports come from the 2009, 2014 model years. The most commonly reported component is Engine,Fuel/Propulsion System (66.7% of reports).

Real CHEVROLET MALIBU Owner Reports

Source: NHTSA Complaints Database

"I have been experiencing an issue with the check engine light coming on almost every fuel fill up i have replaced the cap 3 times already and i keep getting the same code. now i am getting a p0420 code for either the catalytic converter or the oxygen sensor."

— 2009 CHEVROLET MALIBU owner · ENGINE,FUEL/PROPULSION SYSTEM · Filed 05/24/2020

"The shift cable to the transmission became loose while vehicle was running. i was unable to shift the vehicle until the cable was reconnected by hand. the vehicle has an issue with accelerating especially when trying to go highway speeds. it cant flow into traffic normally."

— 2009 CHEVROLET MALIBU owner · POWER TRAIN,ENGINE · Filed 03/24/2018

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

📊 Complaint Trend by Model Year

2

'09

1

'14

Common Causes on CHEVROLET MALIBU

Based on NHTSA complaint component analysis for this vehicle.

ENGINE,FUEL/PROPULSION SYSTEM 66.7%

POWER TRAIN,ENGINE 33.3%

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 CHEVROLET MALIBU? ▾

P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 3 CHEVROLET MALIBU owners have reported this to NHTSA.

What are the most common causes of P0420 on CHEVROLET MALIBU? ▾

Based on 3 NHTSA reports, the most commonly cited components are: Engine,Fuel/Propulsion System, Power Train,Engine. These percentages are based on the component field in owner complaints.

Is P0420 serious on my CHEVROLET MALIBU? ▾

Of 3 NHTSA reports for this code on CHEVROLET MALIBU, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my CHEVROLET MALIBU 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.