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Help Engine Check Light P0420 Code

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AdvanceAuto
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Help Engine Check Light P0420 Code

Postby AdvanceAuto » March 22nd, 2012, 12:15 pm

Code Scanner showed a code P0420 Catalyst Efficiency Below Threshold (Bank 1), I ran super for a little more than a week before this happened i usually fill up with premium. What can i do to solve this problem entirely. I was thinking of removing the Cat can this be done?
the car is a 2007 Subaru Impreza Hatchback Non Turbo engine EL15. Help anyone.

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air wick
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Re: Help Engine Check Light P0420 Code

Postby air wick » March 22nd, 2012, 12:40 pm

my wife has a 2007 hatchback with same EL15 and we run super all the time with no problem.
the error is because of the oxygen sensor, If you reset the ecu the code should go away but if it keeps happening change the oxygen sensor

AdvanceAuto
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Re: Help Engine Check Light P0420 Code

Postby AdvanceAuto » March 22nd, 2012, 4:07 pm

Thanks, I'll reset it and see what happens. One of my Co-Workers actually ran into the same problem after changing to Super. A few post I read they stated to change the Cat others said the Oxygen Sensor, Is there something i can do so that i would never have this problem again?

Nebulous_14
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Re: Help Engine Check Light P0420 Code

Postby Nebulous_14 » March 22nd, 2012, 5:56 pm

You can decat the car and install a MIL eliminator by Farley (3979650).
Got his name a while back, I talked to him last year so he replaces the cat with a pipe.
I never did because the CEL cleared by itself and from reading on the net it seems to be a common problem with these cars.
Change back to premium and run the car for a week it usually goes away for itself.
Changing the oxygen sensors will not help if the readings are within parameters the CEL will come back.
Changing the cat with a good foreign used one (hard to tell) should prevent it from reoccurring.

AdvanceAuto
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Re: Help Engine Check Light P0420 Code

Postby AdvanceAuto » March 26th, 2012, 8:20 am

Thanks alot I'll change back to premium and see how it goes, If that does'nt work i'll try that guy.

Loud Expertz
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Re: Help Engine Check Light P0420 Code

Postby Loud Expertz » April 27th, 2012, 2:17 pm

had that same exact problem, what you need to do to prevent re-occurence is remove the two cats and install the two sensor back onto the exaust but the second sensor use a 1/4 inch spacer to take it out of the flow of the exaust gases and you should also replace the sensors if you have the cash. I did this and have been running super in mine for 2 years now with no engine light.

Nebulous_14
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Re: Help Engine Check Light P0420 Code

Postby Nebulous_14 » April 30th, 2012, 5:36 pm

You could buy a anti spark plug fouler that motorist sells and weld it on to move the rear o2 out of the direct stream of the gas . Cheapest fix and if that don't work then you can do what loud expertz said. I question loud expertz did you notice any loss or gain in performance.

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