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P0420 Diagnostic Trouble Code Discussion for September 2014

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2007 Audi Q7 3.6L Poor Idle Quality, Misfire, MIL Lamp on
Hi there guys, writing this one up before i go home. This 07 Audi Q7 came in after the above mentioned repairs already performed but according to the customer everything is as it was. Same DTC's & driveability concerns. I went as far as doing a visual insp...
September 17, 2014
2006 Chevrolet Express 3500 4.8L Misfire VIN: 1GBHG31V56
P0420: Catalyst System Low Efficiency (Bank 1). miss fire all times, mostly on cylinders 1,6,7 some times 8... on idle or accel all times, checked compression, leak down, back pressure, spark, injecters pulse, noid lights test, all normal or good, smoked intake for leaks none found, fuel trim...LT #1 25% LT...
September 20, 2014
2006 Chevrolet Express 3500 4.8L Misfire VIN: 1GBHG31V56
P0420: Catalyst System Low Efficiency (Bank 1). miss fire all times, mostly on cylinders 1,6,7 some times 8... on idle or accel all times, checked compression, leak down, back pressure, spark, injecters pulse, noid lights test, all normal or good, smoked intake for leaks none found, fuel trim...LT #1 25% LT...
September 22, 2014