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P0420 Diagnostic Trouble Code Discussion for December 2014

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2003 Toyota Sienna CE 3.0L MIL Lamp on VIN: 4T3ZF19CX3
P0420: Catalyst Efficiency Below Normal (Bank 1). ... advance for your willingness to help/provide insight. The story - this old (240K miles) Sienna starting popping a P0420 code approx every couple of months over the last year. It's been working all these years with the original ECM (even though Toyota relea...
December 02, 2014
1997 Mazda Protege DX 1.5L No communication VIN: JM1BC1415V
P0420: Catalyst Efficiency Below Normal (Bank 1). Hi need some assistance from the old school Mazda techs. This car came in for a failed emissions test with a code p420. I was unable to communicate with the ecu to verify the code. Now the problem is no communication with the ecu. I have power and ground at pr...
December 03, 2014
2005 Nissan Altima S 2.5L Poor Idle Quality, Surge, MIL Lamp on VIN: 1N4AL11D95
P0420: Catalyst Efficiency Below Normal (Bank 1). Ok this nissan has been sitting over a year. Batt was toast, and did some brake work, got it running drove for a week or so and lite came on 420 i know is the cat it's toast, the 455 was vent stuck open thats fixed new vent valve. Now the 507, tried cleaning t...
December 03, 2014
2004 Nissan Sentra SE-R 2.5L MIL Lamp on VIN: 3N1AB51D04
P0420: Catalyst Efficiency Below Normal. We have a 2004 sentra here that came in with a cat code and the cat definitely shows bad on scan data during a drive cycle. The issue that bugs me is that the vehicle is staying in open loop all the time even though all the data pids look normal other than the...
December 17, 2014
2006 Honda Pilot EX 3.5L Excessive Emissions, Poor Fuel Economy, MIL Lamp on VIN: 5FNYF28656
P0420: Catalyst Efficiency Below Threshold (Bank 1). Vehicle apppears to run fine. Using scan tool,and viewing O2 sensors Bank 1 appears lazy in switching, Practically a flat line when viewed against the bank 2 ,O2 sensor. Upon increasing RPM they come alive, the B1 sensor is still Weak , the B2 looks like a nor...
December 19, 2014
2004 Nissan Sentra SE-R 2.5L MIL Lamp on VIN: 3N1AB51D04
P0420: Three-Way Catalyst Malfunction. We have a 2004 sentra here that came in with a cat code and the cat definitely shows bad on scan data during a drive cycle. The issue that bugs me is that the vehicle is staying in open loop all the time even though all the data pids look normal other than the...
December 19, 2014