Check engine light Stays on

Getting a PO421 code? Is this a bad CAT? Car is sonata 2002 with a 2.4L with 94k miles. In the last 3,000 miles have had tune-up,new timing chain,new water pump.I understand CAT are
expensive for this type of vechile.
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Most likely, yes, you need a manifold catalytic converter. Check for exhaust leaks and proper oxygen sensor operation. If oxygen sensors are working properly and there are no exhaust leaks, replace the converter.
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Lucked out new gas cap did the trick. Happy Holidays
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A new gas cap won't cure a P0421. What makes you think you've fixed the problem?
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
After looking back, I see the tone of the previous post appears abrasive. It wasn't meant to be. I am indeed interested in why you believe the car is fixed. Did the lamp go out? Did you turn it out and it didn't come back on?
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Lamp went out and hasn't come back on.
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Lamp went out by its self and has not come back on.
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Chances are your catalytic converter is at marginal efficiency. The lamp will probably come back on sooner or later, with the same code.
Since it went out on its own, disconnect the negative battery terminal for about five seconds to clear the code (presuming you're outside the 8/80 warranty period). If you're still within the warranty period, present the car to the dealer for service, hopefully while the code is still present in memory.
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I'll keep you posted. Foot Note: Local newspaper article said certain individuals are stealing CAT for metal value?Some can be taken within minutes.
-- Message posted using http://www.talkaboutautos.com/group/alt.autos.hyundai / More information at http://www.talkaboutautos.com/faq.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.