× 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 January 2006

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 Camry CE 2.2L MIL Lamp on VIN: 4T1BG22K5W
P0420: Catalyst Efficiency Below Normal (Bank 1). cAR CAME IN RUNNING ROUGH WITH CHECK ENGINE LIGHT ON. HAD FRONT O2 SENSOR CODE I FORGET WHICH ONE AND PO420. I FOUND WRONG SENSOR IN FRONT OF CAT. HAD AN O2 SENSOR RATHER THAN A A/F SENSOR. REPLACED WITH A/F SENSOR AND REPLACED PLUGS AND WIRES. RESET COMPUTER....
January 05, 2006
1999 Subaru Forester L 2.5L Excessive Emissions, Poor Idle Quality, MIL Lamp on VIN: JF1SF6352X
P0420: Catalyst Efficiency Below Normal (Bank 1). ... here, this car has been to the dealership, a couple different shops and has wound up in our hands now. This Forester keeps setting P0420 cat eff. codes. It had a head gskt job done at another shop and 8 months later keeps setting this code. No other codes,...
January 06, 2006
1999 Chevrolet Astro 4.3L Poor Idle Quality, Surge, MIL Lamp on VIN: 1GCDM19WOX
P0420: Catalyst System Low Efficiency (Bank 1). ... codes only code p1870. recheck cam retard reads -60 at idle. what is causing the cam retard to go crazy.
January 11, 2006
2002 Toyota Camry SE 2.4L MIL Lamp on VIN: JTDBE32K22
P0420: Catalyst Efficiency Below Normal (Bank 1). ... #P0420. I followed the Toyota diag chart from AllData and came up with a bad catalytic converter diagnosis but I'm left with some questions since I am not that familiar with Toyota. First, the readings on the scan tool for what I think is post cat O2 rea...
January 11, 2006
2001 Chevrolet Venture LS 3.4L Excessive Emissions, MIL Lamp on VIN: 1GNDX03EX1
P0420: Catalyst System Low Efficiency. ... frame data always shows between 600-700rpm. This van originaly had a convertor replaced by another tech about 1 year ago. I got it a couple of weeks ago because of the P0420 DTC. Checked it out and found a dirty MAF and convertor oxygen storage to be low. ...
January 31, 2006