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P0420 Diagnostic Trouble Code Discussion for April 2006

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
1996 Lexus LS400 4.0L MIL Lamp on VIN: JT8BH22F1T
P0420: Catalyst Efficiency Below Normal (Bank 1). this one seems obvious but has any one seen multiple cat failures in such a short time, all readings seem normal this seems obviuous but has anyone seen cat failures after such a short time???
April 01, 2006
2000 Toyota Camry CE 2.2L Excessive Emissions, MIL Lamp on VIN: 4T1BG22K6Y
P0420: Catalyst Efficiency Below Normal (Bank 1). Check Engine light is on. Code P0420 (catalyst efficiency low). Monitored downstream oxygen sensor, working properly except it seems to be switching too often for a catalyst monitor. I don't see the A/F ratio sensor on my scanner so I can't monitor it. My ques...
April 04, 2006
2002 Buick Regal LS 3.8L MIL Lamp on, PO420 VIN: 2G4WB55KX2
P0420: Catalyst System Low Efficiency (Bank 1). This vehicle came to me with a hole burned through the intake phlenum and antifreeze in the cylinders. I replaced the Phlenum and cleaned up the cylinders. upon starting the vehicle discovered the starter was also bad. Replaced starter. After test drivining th...
April 05, 2006
2000 Chevrolet Cavalier 2.2L MIL Lamp on VIN: 1G1JC1245Y
P0420: Catalyst System Low Efficiency. ... 2 times , once with a universal converter, then with a (better) o.e. style aftermarket converter. after second converter, i started thinking maybe the post o2 sensor was giving it a false signal, so i replaced that. it took about a week each time but same ...
April 05, 2006
1997 Toyota Avalon XL 3.0L MIL Lamp on VIN: 4T1BF12B1V
P0420: Catalyst Efficiency Below Normal (Bank 1). WE GOT THIS ONE AFTER ANOTHER SHOP HAD REPLACED THE CAT 3 TIMES OVER A COUPLE MONTHS TIME, AGAIN THE DOWNSTREAM O2 VOLTAGE IS FLUCTUATING WITH THE FRONT ONES INDICATING ANOTHER CAT FAILURE, THIS ONE ONLY A COUPLE WEEKS OLD. NO OTHER CODES ARE PRESENT AND THE C...
April 12, 2006
1996 Ford Windstar GL 3.8L Cuts out, Misfire, MIL Lamp on VIN: 2FMDA5147T
P0420: catalyst system efficency below threshold bank 1. p0340 only hard code,cam sensor wiring has been tested,all grounds back to pcm have been checked,cam sensor and pcm have been replaced,code always resets.found cam sensor out of sync.180 degrees,set up sensor to number 1 cyl tdc.now engine runs better,but p034...
April 15, 2006