P0420 on GMC TERRAIN
What P0420 Means on Your GMC TERRAIN
Real GMC TERRAIN Owner Reports (Source: NHTSA Complaints Database)
"I bought my 2010 GMC Terrain SLE at 160,000. It had a rough start up but the dealer said it was because it was an older car and been sitting for a while. The rough start up never stopped even after replacing the catalytic converter because of code P0420."
"Transmission failure with no warning, torque converter replacement $3,500 around 120k miles. check engine light unable to be diagnosed or repaired succesfully since 100k miles. code p0420 with no catalytic converter issues. every o2 sensor replaced, code will not clear."
"The contact owns a 2013 GMC Terrain. The contact stated that when slowing down to come to a stop, the vehicle was jumping and hesitating, causing the contact to shift into neutral(N) to stop the vehicle and prevent the vehicle from shaking. There was a fuel odor that smelled like rotten eggs."
Data from NHTSA Vehicle Complaints Database. All reports are filed by vehicle owners directly with the U.S. Department of Transportation.
Common Causes of P0420 on GMC TERRAIN
Percentages based on NHTSA complaint component analysis for this vehicle.
Complaint Trend by Year
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if your vehicle is covered.
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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.
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3
Compare repair quotes
Get 2-3 quotes. Dealer vs independent shop prices often differ 30-50% for the same repair.