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Po431 warm up catalyst efficency below threshold bank 2 what does this mean

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Re: Po431 warm up catalyst efficency below threshold bank...

This is an o2 sensor fault,this is the one after the cat.,so there could be two thingd goin on, First the catalytic converter may be faulty,or the sensor its self may be faulty,best way to diagnose is to hook up scan tool and monitor live data and watch the response of that sensor,if it's slow and there are no exhaust leaks near the sensor you probably have faulty sensor,if it respondinc correctly and no leakks then your cat is out of effecincy and needs replaced,if this the case i would replace both. if you have no acces to a scan tool i would check for leaks and if none i would replace sensor alone first since even if that not the fix you wouled had to buy one anyhow when you replace cat

Posted on Oct 30, 2010

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