Check Engine Light On. Help!

CHeck your EGR valve if its clogged perhaps. Its behind by the intake manifold. Clean it out and clear the code and see what happens.

On a side note, it maybe a bad batch of Gasoline as well. Get some 93 Octane and run it through the system. It could also be that the cat is not clean the hydrocarbons well enough and the O2 sensors are picking it up.

Alright will do and i'll see what happens

Chad

It came back on, usually it is off for about a day or so and then pops back on.

Chad

any luck? I am having trouble with the same code.

It might just be an O2 sensor. Mine is on its been on for over a year. Go to Advance auto parts or Auto zone they will scan it for free. but might just be a 02 heater burnt out.

clubnos007 said:

It might just be an O2 sensor. Mine is on its been on for over a year. Go to Advance auto parts or Auto zone they will scan it for free. but might just be a 02 heater burnt out.

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I have a 2002 Dodge Stratus R/T.

I had the code read... P0421: Warm Up Catalyst Efficiency Below Threshold (Bank 1) and P0431: Warm Up Catalyst Efficiency Below Threshold (Bank 2)

Could it be a bad sensor or am I going to have to replace the front two cats?? I just had the rear replaced by an aftermarket type. The dodge part was huge and expensive. I was told the fronts were very expensive. I dont want to replace if i dont have to.

Is there any way to know if the sensor is bad?

clubnos007 said:

might just be a 02 heater burnt out.

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No -- there's a separate code for that.


My advice: If you don't want to replace your pre-cats, do the anti-fouler trick.