Join Now
International Automotive Technicians Network

P0420 Diagnostic Trouble Code Discussion for September 2010

Catalyst Efficiency Below Normal (Bank 1)


Note: This is a professional automotive technician's resource.
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2002 Saturn L200 2.2L MIL Lamp on VIN: 1G8JU54F92
P0420: Catalyst System Low Efficiency (Bank 1). ... on for about a year and a half. Has a code of p0420 and says catalyst system efficience below threshold. Customer to it to local autozone and the told him it needed a convertor. He took car to monroe muffler where they installed a new aftermarket convertor...
September 01, 2010
1999 Chevrolet C1500 Suburban 5.7L MIL Lamp on VIN: 3GNFK16R8X
P0420: Catalyst System Low Efficiency (Bank 1). Vehicle came in from another shop running lean, Found fuel pressure below specs, Other shop had put cheap fuel pump in, Customer took vehicle back to them and they put in a/c delco fuel pump. Runs great now but PO420 code keeps returning, Converter back pressu...
September 02, 2010
2003 Toyota RAV4 2.0L MIL Lamp on VIN: JTEGH20V73
P0420: Catalyst Efficiency Below Normal (Bank 2). ... vehicle has been here with the same problem a few times check engine light with code P420. First time vehicle came in we checked air fuel sensor and oxygen sensors, replaced all sensors. Code went away for a a month then vehicle came back with same code, w...
September 13, 2010