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P0420 Diagnostic Trouble Code Discussion for January 2014

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2001 Chrysler Town & Country EX 3.8L MIL Lamp on VIN: 2C4GP74L91
P0420: Catalyst Efficiency Below Normal (Bank 1). ... set) Replaced faulty EGR. Thought all was well. Customer said the light came on again a week later. Found code P0420 set. Checked pre and post cat o2 signals and found post signal pretty well following the the pre cat si...
January 06, 2014
2003 Saturn Vue 2.2L No Start VIN: 5GZCZ23D13
P0420: Catalyst System Low Efficiency (Bank 1). Thanks in advance for your help guys! The vehicle came in cranking good, no start. It smelled of raw fuel so I started checking the ignition system. Found spark plug gaps ranged from 0.090-0.100, engine was flooded. I blew out the combustion chambers, through...
January 08, 2014
2001 Honda Accord LX 2.3L p0420 VIN: 1HGCG56411
P0420: Catalyst Efficiency Below Threshold (Bank 1). Car runs great, has code P0420, everything appears fine, need second opinion. I see this as a bad converter, am I missing anything? The converter manufacturer is giving us the run around. Not OE lesson learned...
January 13, 2014
2006 Pontiac G6 2.4L MIL Lamp on VIN: 1G2ZF55B26
P0420: Catalyst System Low Efficiency (Bank 1). Vehicle came in 2 weeks ago with p0420 code. Asked for rear 02 sensor to be changed. Sensor was replaced and after 1 week of driving the light came back on with the same code. Currently in the shop. I have look at both front and rear 02 sensor reading and they...
January 17, 2014
2003 Chrysler Town & Country LX 3.3L Excessive Emissions, Poor Idle Quality, Hesitation, Cuts out, Stall, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 2C4GP44313
P0420: Catalyst Efficiency Below Normal (Bank 1). Customer complaint of very hard start, decreased fuel mileage, misfiring, very rough idle starting last summer. Tune up and O2 sensor replaced at that time. Plugs were worn and O2 sensor not switching at all and pinned over 1v. Once repairs done, ran perfect a...
January 23, 2014