Join Now
International Automotive Technicians Network

P0420 Diagnostic Trouble Code Discussion for December 2007

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
1998 Toyota Sienna LE 3.0L Poor Fuel Economy, MIL Lamp on VIN: 4T3EZF13C9
P0420: Catalyst Efficiency Below Normal (Bank 1). ... has me lost. Code p0420 low cat efficiency bank 1. Bank 1 sensor switching but slow. Replaced o2 sensor with aftermarket NGK sensor. Sensor readings better. Retuned to customer. One month later code is back. Graph O2 sensor, switching slow again like a slu...
December 13, 2007
2002 Volkswagen Jetta GLS 1.8L MIL Lamp on VIN: 3VWSE69M72
P0420: . ... appearing of p0420.
December 14, 2007
2005 Honda Pilot EX 3.5L Misfire, MIL Lamp on VIN: 5FNYF18485
P0420: Catalyst Efficiency Below Threshold (Bank 1). ... codes for #3 and #6 cyls. During our road tests,p0420 Cat efficiency below threshold-bank one, set also. We performed tune-up with dealer oem plugs. Car still has a ramdom intermittent misfire on any cyl it want to. Not just ...
December 31, 2007
1998 Toyota Sienna LE 3.0L Poor Fuel Economy, MIL Lamp on VIN: 4T3EZF13C9
P0420: Catalyst Efficiency Below Normal (Bank 1). ... has me lost. Code p0420 low cat efficiency bank 1. Bank 1 sensor switching but slow. Replaced o2 sensor with aftermarket NGK sensor. Sensor readings better. Retuned to customer. One month later code is back. Graph O2 sensor, switching slow again like a slu...
December 13, 2007
2002 Volkswagen Jetta GLS 1.8L MIL Lamp on VIN: 3VWSE69M72
P0420: . ... appearing of p0420.
December 14, 2007
2005 Honda Pilot EX 3.5L Misfire, MIL Lamp on VIN: 5FNYF18485
P0420: Catalyst Efficiency Below Threshold (Bank 1). ... codes for #3 and #6 cyls. During our road tests,p0420 Cat efficiency below threshold-bank one, set also. We performed tune-up with dealer oem plugs. Car still has a ramdom intermittent misfire on any cyl it want to. Not just ...
December 31, 2007