SES light

[Go4broke]

I have had my SES light on for a few days now and finaly when to Auto Zone to have them see what is was. the code P0420 came up 2 times and read Catyilst system below threshold. does any one know what that means? the guy there said it had something to do with my cat but my cat. is like 6 months old.

[Pathogen]

(Scratches head, pulls out bible)
P0420 - Catalyst system below threshold, left bank, same thing for P0421
Haynes Manual 6-20 Emissions and Engine Control Systems
10) Catalytic Converter
<blockquote>quote:</font><hr>
The Catalytic Converter is an emission control device added to the exhaust system to reduce poluutants from the exhaust gas stream. These systems are equipped with a single bed monolith catalytic converter. This monolithic converter contains a honeycomb mesh wich is also coated with two types of catalysts. One type is the oxidation catalyst whie the other type is a three-way catalyst that contains platinum and palladium. The three-way catalyst lowers the levels of oxides of nitrogen (NOx) as well as hydrocarbons (HC) and carbon monoxide (CO) emissions. The oxidation catalyst lowers the levels of hydrocarbons and carbon monxide. (yadda, yadda, yadda)
<hr></blockquote>

The equipment to test (yadda yadda) expensive, sophisticated . . . check vehicle for leaks, damage or corrosion . . . replace if problems are found.

Cat's break up - it happens. -- best thing to do, "Almost-A-Cat" . . . but I didn't suggest it ;) .

[Oryan02]

How's your O2 sensor? Do you have a higher flowing cat? High flow cats will cause the ses light to illuminate.

[Go4broke]

well the light came on on the way to work today so I took it to the shop that installed my exhaust and they found a leek so they fix it.

[ChikNz]

I got code 0420 after I did my exhaust, didnt come on for about 3 days but then I just reset the computer and it went away.