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  #11  
Old 05-20-2006, 04:44 PM
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

probably the cat.
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  #12  
Old 06-05-2006, 03:17 AM
 
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

About a week ago the Check Engine Light went out while driving, and has stayed off. What's that about?
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  #13  
Old 08-30-2006, 02:20 AM
 
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

The check engine light has not returned since the last post back in early June. Is the code still stored in the ECU?
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  #14  
Old 08-30-2006, 03:45 AM
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

any time that the chk engine lite comes on,, it will store a code in the ecu..
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  #15  
Old 08-30-2006, 04:38 PM
 
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

I am just wondering if I am gonna be able to pass emissions test.
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  #16  
Old 08-30-2006, 11:34 PM
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

1. if your cat is not properly working it will affect your fuel milage as the ECU will no longer be able to accurately monitor if that cat is working

2. Not a change of passing if the cat is bad
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  #17  
Old 02-06-2008, 07:31 PM
sleeper408
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

Hello all. I decided to resurrect this thread instead of starting a new one. So after some problemsand havingthe EGR valve replacedand IAC valve fixed, I get a new code today.The code is p0420 and I have done a search on this forum already for some answers and they have been helpful. I do have some additional questions though thatmaybe senior membersand Honda Techs could answer?

My girlfriend and I went to have the vehicle smogged today and it passed no problem. Then after driving a few hours later, the check engine light came on. I pulled the code andit says it is "bank 1."

Here are the results:
Average15mph/25mph Measured
HC:9-----74-----1
CO: .02----.03 .02----.11
NO: 57-----50122-----3


I'm really baffled how she could have passed smog if the cat was really bad along?

-This leads me to suspect that it might be theo2 sensor instead?

-How badly will the code affect the car's fuel economy (MPG)?

-How much is a new catalytic converter? o2 sensor? Best place (cheapest) to purchase it from?


Thanks in advance,
Theo
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  #18  
Old 02-07-2008, 12:59 PM
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

a simple cat test put the gas to the floor then really fast and hard hit the brakes if the peddle keeps pressure the cat is not clogged if it goes to the floor you got a clogged cat that is a test with no scan tool and most likely your car is bad



I was just looking at some cat things under where i am posting now and yes the cat will effect gas milage the o2 just reads the a/f after the cat and before the cat so if the cat isn't working the o2 isn't working correctly either. It will be either giving more fuel then needed or less rich or lean laymens terms. The cat is there to burn hydrocarbons (parcially burned/ unburned fuel) so if you have to many HC's you will loose fuel economy
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  #19  
Old 02-07-2008, 01:03 PM
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Default RE: What does "Catalyst system efficiency below threshold" code mean?

sleeper 408 you need to say what car it is and if it is odb2 or 1/0 if it is odb 2 and there is no check engine light the car will pass since the car doesn't go on rollers any more with a sniffer. All they check in odb2 is evaporative emmisions and engine codes if it went on the rollers then i am not sure it has been a while since i did any emissions stuff so but those numbers don't look too bad.
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Old 02-07-2008, 01:03 PM
 
 
 
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199, accord, bb, cat, catalyst, catalytic, civic, code, converter, efficency, efficiency, gor, honda, p0420, system, threshold, trouble


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