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2002 Chevrolet Impala 3.4L MIL Lamp on
Posted to GM Driveability on 9/27/2007 14 Replies

Car came in with P0420 code (Catalyst System Low Efficiency) running fine. Checked the rear O2 sensor and found too much activity. Replaced the after market cat with OEM cat and rear O2 sensor.

Drove the car two miles and P0420 code came back. Rechecking, I f...

14 Replies Received (View Replies)

  Related Documents & Media  2002 Chevrolet Impala

 
Message Closed w/FIX

car Vehicle Data

2002 Chevrolet Impala

VIN 2G1WF55E72
Engine3.4 L / 6 cyl / GAS
Trans4-speed Automatic (Electronic)
DeliveryFI
EmissionsOBD-II Compliant
SymptomsMIL Lamp On
OccursAlways

Trouble Codes

P0420Catalyst Efficiency Below Threshold (Bank 1)
Message Closed w/FIX

car Vehicle Data

2002 Chevrolet Impala

VIN 2G1WF55E72
Engine3.4 L / 6 cyl / GAS
Trans4-speed Automatic (Electronic)
DeliveryFI
EmissionsOBD-II Compliant
SymptomsMIL Lamp On
OccursAlways

Trouble Codes

P0420Catalyst Efficiency Below Threshold (Bank 1)