Join Now
International Automotive Technicians Network

P0420 Diagnostic Trouble Code Discussion for November 2008

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 Volkswagen Jetta GLX 2.8L Surge, Poor Fuel Economy, MIL Lamp on VIN: 3VWTH69M12
P0420: Catalyst efficiency below threshold bank 1. Okay folks, this one is long so bear with me. Here goes with my current nightmare. Car belongs to my neighbor. The check engine light came on and he had one of the parts houses do their "free code scan" and it's gone downhill since. The code was for a ...
November 02, 2008
2001 Toyota Camry CE 2.2L MIL Lamp on VIN: 4T1BG22K61
P0420: Catalyst Efficiency Below Normal (Bank 1). ... had replaced it with an aftermarket part because the flex pipe had cracked.Car now has check engine light on with code P0420. So do I replace the exhaust manifold and the rear pipe with Toyota parts or replace the front pipe with a Toyota part? How does th...
November 04, 2008
2002 Volkswagen Jetta GLX 2.8L Surge, Poor Fuel Economy, MIL Lamp on VIN: 3VWTH69M12
P0420: Catalyst efficiency below threshold bank 1. Okay folks, this one is long so bear with me. Here goes with my current nightmare. Car belongs to my neighbor. The check engine light came on and he had one of the parts houses do their "free code scan" and it's gone downhill since. The code was for a ...
November 08, 2008
2001 Honda Odyssey LX 3.5L MIL Lamp on VIN: 2HKRL18561
P0420: Catalyst Efficiency Below Threshold (Bank 1). CEL on with a PO420 code. Cat efficiency Low. Vehicle runs very well. The vehicle has only two 02 sensors running this system . First - looking at both 02 sensors on my Solus in the customized data view , the 02 sensors start out cold switching alike and then ...
November 10, 2008
2001 Toyota Tacoma DLX 2.7L MIL Lamp on VIN: 5TEWM72N21
P0420: Catalyst Efficiency Below Normal (Bank 1). ... sensor, and the cat back exhaust replaced. customer stated that light came on after muffler was replaced. a/f sensor was replaced and he said mileage improved. we assumed it was stuck and had overheated the pre cat, since it had an audible rattle. we repl...
November 11, 2008
2003 Pontiac Vibe 1.8L MIL Lamp on VIN: 5Y2SL62873
P0420: Catalyst System Low Efficiency. ... year now replaced cat and o2 sensors same code had aftermarket cat and then a oem cat still a couple months later p0420 code returns no service bullintens on programming issues any ideas would be helpful
November 12, 2008
2001 Toyota Tacoma DLX 2.7L MIL Lamp on VIN: 5TEWM72N21
P0420: Catalyst Efficiency Below Normal (Bank 1). ... sensor, and the cat back exhaust replaced. customer stated that light came on after muffler was replaced. a/f sensor was replaced and he said mileage improved. we assumed it was stuck and had overheated the pre cat, since it had an audible rattle. we repl...
November 12, 2008
2002 Volkswagen Jetta GLX 2.8L Surge, Poor Fuel Economy, MIL Lamp on VIN: 3VWTH69M12
P0420: Catalyst efficiency below threshold bank 1. Okay folks, this one is long so bear with me. Here goes with my current nightmare. Car belongs to my neighbor. The check engine light came on and he had one of the parts houses do their "free code scan" and it's gone downhill since. The code was for a ...
November 02, 2008
2001 Toyota Camry CE 2.2L MIL Lamp on VIN: 4T1BG22K61
P0420: Catalyst Efficiency Below Normal (Bank 1). ... had replaced it with an aftermarket part because the flex pipe had cracked.Car now has check engine light on with code P0420. So do I replace the exhaust manifold and the rear pipe with Toyota parts or replace the front pipe with a Toyota part? How does th...
November 04, 2008
2002 Volkswagen Jetta GLX 2.8L Surge, Poor Fuel Economy, MIL Lamp on VIN: 3VWTH69M12
P0420: Catalyst efficiency below threshold bank 1. Okay folks, this one is long so bear with me. Here goes with my current nightmare. Car belongs to my neighbor. The check engine light came on and he had one of the parts houses do their "free code scan" and it's gone downhill since. The code was for a ...
November 08, 2008
2001 Honda Odyssey LX 3.5L MIL Lamp on VIN: 2HKRL18561
P0420: Catalyst Efficiency Below Threshold (Bank 1). CEL on with a PO420 code. Cat efficiency Low. Vehicle runs very well. The vehicle has only two 02 sensors running this system . First - looking at both 02 sensors on my Solus in the customized data view , the 02 sensors start out cold switching alike and then ...
November 10, 2008
2001 Toyota Tacoma DLX 2.7L MIL Lamp on VIN: 5TEWM72N21
P0420: Catalyst Efficiency Below Normal (Bank 1). ... sensor, and the cat back exhaust replaced. customer stated that light came on after muffler was replaced. a/f sensor was replaced and he said mileage improved. we assumed it was stuck and had overheated the pre cat, since it had an audible rattle. we repl...
November 11, 2008
2003 Pontiac Vibe 1.8L MIL Lamp on VIN: 5Y2SL62873
P0420: Catalyst System Low Efficiency. ... year now replaced cat and o2 sensors same code had aftermarket cat and then a oem cat still a couple months later p0420 code returns no service bullintens on programming issues any ideas would be helpful
November 12, 2008
2001 Toyota Tacoma DLX 2.7L MIL Lamp on VIN: 5TEWM72N21
P0420: Catalyst Efficiency Below Normal (Bank 1). ... sensor, and the cat back exhaust replaced. customer stated that light came on after muffler was replaced. a/f sensor was replaced and he said mileage improved. we assumed it was stuck and had overheated the pre cat, since it had an audible rattle. we repl...
November 12, 2008