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P0420 Diagnostic Trouble Code Discussion for November 2014

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2006 BMW M5 5.0L MIL Lamp on VIN: WBSNB93506
P0420: Cat efficiency bank 1 generic. Hey BMW Techs. Just looking for a little information and confidence before i sell a huge cat job on this M5. As far as i can tell its needs new cats. Rear O2's are switching a little at idle (.3v - .6v) . No issues with any adaptations, vac leaks, exhaust leak...
November 07, 2014
2006 Chevrolet Cobalt LS 2.2L Poor Idle Quality VIN: 1G1AK15F56
P0420: Catalyst System Low Efficiency. thanks in advance guys this colbalt has me stumped it came in for low cat efficancy code checked back pressure 1.5 psi ay 2500 rpm downstream o2 about 550mv scanner data not changed o2 mv lower sent customer home next day shes back code back freeze frame said ...
November 18, 2014