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P0420 Diagnostic Trouble Code Discussion for July 2005

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2002 Chevrolet Silverado 1500 4.3L MIL Lamp on VIN: 1GCEC14W62
P0420: Catalyst System Low Efficiency (Bank 1). hi guys thanks ahead of time, what i have is code po420 comes on after truck is driven ten miles evert time, started after it came in with hard start when wet, so we tune it up with new wires, cap, rotor, coil, check all four 02 sensor they are switching good,...
July 22, 2005
2001 Buick Regal LS 3.8L MIL Lamp on VIN: 2G4WB55K11
P0420: Catalyst System Low Efficiency (Bank 1). car came in with no power,cleaned maf,replaced fuel filter{clogged{.did back pressure test and found convertor clogged.installed new convertor obdll compliant.car came back following week with cat eff.code.have no access to gas analyzer any help would be appre...
July 26, 2005