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

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

"P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 8 CHEVROLET EQUINOX owners have reported this to NHTSA."

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

"Based on 8 NHTSA reports, the most commonly cited components are: Engine, Vehicle Speed Control,Engine, Wheels,Fuel/Propulsion System. These percentages are based on the component field in owner complaints."

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

"Of 8 NHTSA reports for this code on CHEVROLET EQUINOX, 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 EQUINOX 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 EQUINOX

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.

8 CHEVROLET EQUINOX owners have reported this issue to NHTSA across model years 2010-2014. Most reports come from the 2011, 2010 model years.

Real CHEVROLET EQUINOX Owner Reports

Source: NHTSA Complaints Database

"I put in a new cadillac converter and every time i turn around i have to change the o2 sensors bank1 02 sensor keeps giving me p034 & p054 in a permanent p0420 it gets very expensive changing the same repairs over and over again ."

— 2010 CHEVROLET EQUINOX owner · VEHICLE SPEED CONTROL,ENGINE · Filed 02/24/2018

"I just recently bought a 2011 chevy equinox lt awd, and soon after i began driving it, the check engine light came on with code p0420 catalyst system efficiency below threshold."

— 2011 CHEVROLET EQUINOX owner · ENGINE · Filed 12/06/2019

"Rattle and noise in the front passenger side of vehicle as soon as vehicle is turned on and while in motion, making weird noises and movements while driving, occasional hard shift, back rear drivers tire losing pressure for no reason, pulling code for p0420, did a google search and seen multiple com"

— 2011 CHEVROLET EQUINOX owner · WHEELS,FUEL/PROPULSION SYSTEM · Filed 11/26/2019

"Driving down the highway going about 70 miles per hour over a bridge. my vehicle started loosing power. about 2 miles after the bridge the engine light came on and the engine shut off. never came back on."

— 2011 CHEVROLET EQUINOX owner · ENGINE,FUEL/PROPULSION SYSTEM · Filed 11/23/2018

"For the second time since i have owned the car new major engine work was undertaken. 1st was a timing chain wear issue causing engine noise at about 50k miles. next was a near total engine rebuild due to excess oil consumption where rings, bearings, pistons etc at gm warranty cost."

— 2011 CHEVROLET EQUINOX owner · ENGINE · Filed 12/15/2015

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

📊 Complaint Trend by Model Year

1

'10

5

'11

1

'12

1

'14

Common Causes on CHEVROLET EQUINOX

Based on NHTSA complaint component analysis for this vehicle.

ENGINE 37.5%

VEHICLE SPEED CONTROL,ENGINE 12.5%

WHEELS,FUEL/PROPULSION SYSTEM 12.5%

ENGINE,FUEL/PROPULSION SYSTEM 12.5%

UNKNOWN or OTHER,ENGINE 12.5%

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 EQUINOX? ▾

P0420 indicates: Catalyst System Efficiency Below Threshold Bank 1. This is a emission controls code. 8 CHEVROLET EQUINOX owners have reported this to NHTSA.

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

Based on 8 NHTSA reports, the most commonly cited components are: Engine, Vehicle Speed Control,Engine, Wheels,Fuel/Propulsion System. These percentages are based on the component field in owner complaints.

Is P0420 serious on my CHEVROLET EQUINOX? ▾

Of 8 NHTSA reports for this code on CHEVROLET EQUINOX, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my CHEVROLET EQUINOX 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.