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P0420 Diagnostic Trouble Code Discussion for June 2014

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2000 Toyota 4Runner SR5 3.4L MIL Lamp on VIN: JT3HN86R2Y
P0420: Catalyst Efficiency Below Normal (Bank 1). ... failure. p0420. i replaced cats verified fuel trims and car went out. came back a month later with p1135, p1130,(afr heater circuit failure) p0171 (lean bank 1). replaced sensor ratios went to normal. soon after the converter code comes back. I defected ca...
June 10, 2014
2001 Ford Excursion XLT 6.8L MIL Lamp on
P0420: catalyst effeciency bank 1. sorry for the limited info. this is the problem. vehicle came in with 0420 code. checked both front o2 sensors and theyre fine. went to check rear sensor and it wasn't there. found the connector from the vehicle hanging by itself, but no sensor or even a bung ...
June 22, 2014