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P0420 Diagnostic Trouble Code Discussion for October 2012

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2006 Toyota Corolla S 1.8L MIL Lamp on VIN: 1NXBR32E06
P0420: Catalyst Efficiency Below Normal (Bank 1). ... smogged, (california)... vehicle came in with p0420, (cat system efficiency below threshold bank 1). found an exaust leak between manifold to cat donut gskt, replaced it. replaced downstream HO2 sensor but code returns. exaust emissions are way to good to ...
October 02, 2012
2000 Toyota 4Runner SR5 3.4L MIL Lamp on VIN: JT3HN86R8Y
P0420: Catalyst Efficiency Below Normal (Bank 1). This 4 runner has history of setting p0420.this is a california vehicle. customer has had convertor replaced less than two yrs ago.front o2 recently replaced.Dealer wants $2400 for a a pair of convertors, I talked to a local exhaust shop who told me these mode...
October 11, 2012
2002 Toyota Sienna LE 3.0L MIL Lamp on VIN: 4T3ZF13C42
P0420: Catalyst Efficiency Below Normal (Bank 1). ... time to read this! This Sienna Intermittently throws an P0420b code. When this started we first put in the three sensors, based on the mileage. Code came back in one month. Next after watching the rear O2 sensor on numerous test drives, we saw the sensor...
October 31, 2012