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P0420 Diagnostic Trouble Code Discussion for January 2011

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2006 Ford F-150 XLT 5.4L Stall, MIL Lamp on VIN: 1FTPW12V36
P0420: cat eff. need help on this one! this vechile wont idle i cleared the codes and they didnt come back all pids look good. what am i missing?
January 12, 2011
2005 Chrysler Pacifica Limited 3.5L Hesitation, Surge VIN: 2005CHRYLE
P0420: Catalyst Efficiency Below Normal (Bank 1). The vehicle has a p0420 cat. efficiency code.Checked the basics.Fuel pressure in spec.Removed the upstream 02 sensor and installed a pressure gauge.It has 2 psi back pressure at idle and 4-5 psi back pressure in gear and brake standing.Phoned the dealer for co...
January 14, 2011
2003 Jaguar X-Type 2.5L Poor Fuel Economy VIN: SAJEA51D73
P0420: catalyst effeciencybank 1. ... reduced fuel economy.He has owned this car for 4 years and drives mostly highway.He states that fuel mileage went from 30 mpg to 24,suddenly. Car drives fine.Checked for engine codes,originally had p0171 and p0174,system lean bank 1 and 2 and P0420,cataly...
January 28, 2011
1996 Jeep Cherokee Classic 4.0L Excessive Emissions VIN: 1J4FJ78SXT
P0420: Catalyst Efficiency Below Normal (Bank 1). Intermittently the upstream O2 sensor shows a full rich condition and the post cat sensor follows suit, Checked the following with scanner and fuel pressure gauge attached, Map sensor OK, Fuel pressure OK, Coolant temp OK, No obvious vacuum leaks or exhaust le...
January 31, 2011