Engine code p0420 on 2002 Chevrolet Express Van V8
Engine light came on checked problem and got code P0420 with the message, Catalyst Efficiency Below Threshold (Bank 1). The only symptoms are running a little rough at idle and seems to be using a lot of gas (a little over 10mi/gallon). It's the larger V8. We are thinking it's the rear 02 sensor but any information you could offer would be appreciated. Thank you!!!
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Re: engine code p0420 on 2002 Chevrolet Express Van V8
the code you speak of relates strictly to the catalytic converter. it is possible there is a faulty sensor, however that choice is highly unlikely. Catalytic converters carry a 5/50 7/70 and 8/80 warranty depending upoin the state you live in...this may be a repair covered under manufacturers warranty. this code is becoming very prevelant in many auto lines as a result of the insurgence of ethanol dilution of our fuels. the "10%" ethanol sticker is located on most pumps. Most vehicles on the road today are not flex fuel capable and this ethanol is wreaking havoc on our fuel and emission systems, especially the catalytic converters. the converters are caked with deposits from the ethanol, reducing its effeciency. if your have access to well worth branded products (not available in ANY parts store, typicaly dealers and repair shops only) try adding on succesive tank loads of fuel their product called Octi-Plus. this products helps remove ethanol products, and very well may save yoiu big $$$ for that converter repair bill...i hope this helps..check out this link....
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Got it scanned and it's P0420: Catalyst efficiency below thresholdbank 1. They said it could be a bad catalytic converter or oxygen sensor. I borrowed a scanner and tried to measure the oxygen sensor readings over time.Sep 8, 2011
0174 is system too lean, right bank. 0420 is catalyst sytem efficiency below threshold, left bank. fix would be either oxygen sensor or catalytic converter replacement possibly would need both. note: this veh would possibly have up to 4 oxygen sensors, but cause of problem would be the ones coming off manifolds before the catalytic converter possibly in manifold or y-pipe/down pipe.
Hi Charlie, Diagnostic Test Codes (DTCs) P0420 and P0430 ar "Catalyst Efficiency" codes. These simply mean that the catalytic converters in your vehicle are not performing the way they should be. To fix these codes, you will most likely have to replace the converters. However, these codes do NOT indicate why your engine wil not start. There are many things that can cause an engine to not start. Many of which may or may not set fault codes. You need to determine if the engine is getting fuel and ignition first then go from there.
P0420 = Catalyst System Efficiency Below ThresholdCatalyst System Efficiency Below Threshold.
This means that the secondary O2 sensor detects that the catalytic converter isn't working as efficiently as it should.
This engine code can be triggered by any one of the following:
1.) The catalyst in the catalytic converter is cracked, clogged, or otherwise damaged. 2.) The secondary O2 sensor is malfunctioning. 3.) There is an exhaust leak. 4.) The computer unit is faulty