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2003 Chevrolet Malibu 3.1L Excessive Emissions, MIL Lamp on
Posted to GM Driveability on 7/13/2009 16 Replies

reoccuring 420 does any one else see this problem on gm mainly on 3.1 and 3.4 several cats have been installed even heavy metal cats always fails 420 no reflahs found for this car what is the fix?

16 Replies Received (View Replies)

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car Vehicle Data

2003 Chevrolet Malibu

VIN 1G1ND52J83
Engine3.1 L / 6 cyl / GAS
Trans4-speed Automatic (Electronic)
DeliveryFI
EmissionsOBD-II Compliant
SymptomsExcessive Emissions, MIL Lamp On
OccursAlways

Trouble Codes

P0420Catalyst Efficiency Below Threshold (Bank 1)
Message Closed

car Vehicle Data

2003 Chevrolet Malibu

VIN 1G1ND52J83
Engine3.1 L / 6 cyl / GAS
Trans4-speed Automatic (Electronic)
DeliveryFI
EmissionsOBD-II Compliant
SymptomsExcessive Emissions, MIL Lamp On
OccursAlways

Trouble Codes

P0420Catalyst Efficiency Below Threshold (Bank 1)