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P0420 Diagnostic Trouble Code Discussion for September 2008

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2003 Pontiac Grand Am SE 3.4L Poor Fuel Economy, MIL Lamp on VIN: 1GNNF52E63
P0420: Catalyst System Low Efficiency. a brief thanks to all. first i have ran into this problem dont know where to start. customer came in one day about needing a tune up . just plugs ..request by customer. replaced plugs cust. takes car home a week later car gets tow in, fuel pump went out replac...
September 03, 2008
2002 Volvo S60 2.4L MIL Lamp on VIN: YV1RS61R52
P0420: catalytic converter effiency. hi everyone. i'am wondering if any of you have installed a d.e.c aftermarket catalytic converter on one of these non turbo s60's? we installed one last month on this 2002 s60 after it came in with a po420 cat effiency code. the car left for about 10 days then ...
September 03, 2008
1996 BMW Z3 Roadster 1.9L MIL Lamp on VIN: 2WT34HJ465
P0420: Bank 1 cat oxygen storage inefficient. Verifired code and replaced precat O2 as it seemed a bit lazy. Hooked scope up to both O2s and test drove at highway speeds. First thing I noticed is post cat O2 takes quite a bit of driving to light off ( about 10 minutes). Pre and post voltages are swinging ...
September 04, 2008
1998 GMC K1500 Suburban SLE 5.7L poor acceleration VIN: 3GKFK16R0W
P0420: Catalyst System Low Efficiency (Bank 1). suspecting fuel pump. ondemand says that fuel pressure should be above 60 psi constantly and napafix says it should be appx 60 psi with a 5-10 drop at idle what is correct? only has 51 psi at idle. also low amp probe test shows a pump spinning at 10,500 rpm bu...
September 09, 2008
2004 Subaru Forester X 2.5L MIL Lamp on VIN: JF1SG63614
P0420: Catalyst Efficiency Below Normal (Bank 1). ... here that will intermittently set a p0420 code and will show mode 6 data of tid $01 cid$01 and/or tid$03 cid$01 fail. Scan data looks the same when system passes or fails. Has anybody seen this problem? also can anyone tell me what components and tests the...
September 12, 2008
2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DRO7Y41
P0420: Catalyst Efficiency Below Normal (Bank 1). ... sensors and the maf sensor codes po300, po171, p1145 all went away, But were replaced with p1491 (evap) po420 (cat efficiency) po430 (cat efficiency)..These "new codes" make me suspect that the system is doing a more complete self test now that the...
September 23, 2008