× Auto Repair Pros Member Benefits TechHelp Knowledge Base Forums Resources My iATN Marketplace Chat Pricing About Us Join Industry Sponsors Video Members Only Repair Shops Auto Pro Careers Auto Pro Reviews
Join Now
International Automotive Technicians Network

P0420 Diagnostic Trouble Code Discussion for November 2011

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
2008 Ford F-250 Super Duty XLT 5.4L poor power VIN: 1FTSX21518
P0420: cat efficiency. this is an informational request only, wil post the needed informaiton as the fix. Vehicle comes from a used car lot and has no history. The first visit was for an engine light - retreive po420... cleared, did not pursue andreleased back to dealer at there r...
November 07, 2011
2002 Jaguar X-Type 2.5L cat. efficiency VIN: SAJEB51D62
P0420: catalyst system efficiency below thresholdbank 1. ... P0303,P0301,P0300,P1316,P1313(misfire codes); P0174(system too lean bank 2); P0420,P0430 (catalyst system efficiency below threshold bank 1&2). random misfire was caused by oil seeping inside spark plug hole due to leaking brea...
November 11, 2011
2007 Subaru Impreza Outback Sport 2.5L MIL Lamp on, cruise light flashes VIN: JF1GG63677
P0420: Catalyst Efficiency Below Normal (Bank 1). Car sets p0420 cat code about every three weeks. Car drives 300 miles per day usually. Haven't gotten code back in 65 miles of test driving. Should the afr sensor stay above 2v all the time? When "check engine" illuminates the car has been in cruise co...
November 14, 2011
2001 Toyota Camry CE 2.2L Excessive Emissions, MIL Lamp on VIN: 4T1BG22K31
P0420: Catalyst Efficiency Below Normal (Bank 1). ... light on, P0172, and P0420. The spark plugs had not been replaced and they were wore out. Had them replaced and also install a cat. Drove the car for a test drive no problem, after the car sit in the lot for couple of hours and we had to move it the check ...
November 19, 2011
2000 Honda CR-V EX 2.0L Cuts out, Stall, MIL Lamp on VIN: JHLRD186XY
P0420: Catalyst Efficiency Below Threshold (Bank 1). ... all for reading this!here we go!have this car due to a recommendation from one of my customers cause the owner of the car been so upset to his previous mechanic.this car came due to a stall and sometimes no start.the other shop had tuned up saying to the o...
November 28, 2011