Engine Check Light

[Dappa1771]

My engine check light came on on my 99 Protege Like a week ago ang I went to autozone and they check it for me and it came up with the code P0420 (something about a catyalic converter...and the guy told me to put fuel injection clearner when they tank gets low...and then full it up....and the light should go out...by the time it get to half tank...but the light is still on...So I went back to autozone and someone else in autozone told me I need a (catyalic converter) Do need to go buy a catyalic converter or do I just need a fluid flush..? because I check autozone, advance auto parts..and no one had a catyalic converter for a 99 Protege..How can I fix this code..?

[Emode]

are you running any kind of exhaust?
if so do you have cats?
thats what i get , but i have a catless exhause....maybe you have a leak?also how many miles are on the car?

[Dappa1771]

No...not running no kind of exhaust...everything on the car is what came with the car....998,857

[jaman]

my dad's '00 protege had the catalytic converter replaced as part of the emssion warranty (something like 7 yrs or 120km). make sure you check the emission related warranty, you might still be covered.

[hi-perf]

either that or a faulty o2 sensor.

[Dappa1771]

Thanks everyone for your help..I will check the warranty info as well as check if it's a faulty o2 sensor....I friend of mine was saying it might be a o2 sensor problem as well....I will check that out...

[2000RedProtege]

This may seem simple but the same happened with my 2000 and all it was was that I wasn't turning the gas cap enough

[Matthew]

you have 998,857 miles on your car?

[Dexter]

you have 998,857 miles on your car?
i thought i was the only one to notice that...

[Matthew]

lol i was like WTF!!!

[Dappa1771]

Yes ..I now have over 100,000 miles on my car (wiggle) I did alot of trips from NC to NY...I reset the engine check light last night.. I will see how long it takes to come back on...again...I use to have the gas cap problem..but that went away now the P0420 code is starting to come up...I test the O2 sensor and that was the problem...So I will start to check the catalylic converter.. to see if the is a tempreture difference with the front a rear converter...Then I will see if I can find a converter for my 99 protege is that the problem...but the guy at autozone said they don't carry that part....but I should avoid the dealer at all cost if possible....

[gbvang]

I'm having the same problem with my '99 protege. I got a diagnostics check a few months ago, as well as a few days ago, and the code read PO402 and the guy recomended me to go to a mazda dealership for a possible EGR valve problem. He recomends me go there because it'll be covered under the factory emmissions warrenty.

I'm car illiterate, and I've been reading around finding out if other people had this problem, and as it turns out, its quite common. Now, I'm having seconds thoughts about taking it in when it probably won't even fix the check engine light.

Any suggestions before I take it in? Thankx.

[MikeBlueP5]

if its a emissions related problem and they fix it under warranty then yes it will eliminate the cel. I would at least call the dealership and ask if its still under warranty. Or if you dont wanna call go look in all the paperwork that came with the car it should tell all the warrantys and everything. Good luck

[PatMSP]

<TABLE borderColor=#0000ff width=420 border=1><TBODY><TR><TD vAlign=top>P0420 </TD><TD vAlign=top>Catalyst System Efficiency Below Threshold (Bank 1)</TD></TR></TBODY></TABLE>

http://autorepair.about.com/cs/troubleshooting/l/bl_obd_4.htm

[patj29039]

My engine check light came on on my 99 Protege Like a week ago ang I went to autozone and they check it for me and it came up with the code P0420 (something about a catyalic converter...and the guy told me to put fuel injection clearner when they tank gets low...and then full it up....and the light should go out...by the time it get to half tank...but the light is still on...So I went back to autozone and someone else in autozone told me I need a (catyalic converter) Do need to go buy a catyalic converter or do I just need a fluid flush..? because I check autozone, advance auto parts..and no one had a catyalic converter for a 99 Protege..How can I fix this code..?

[GNO]

you have 998,857 miles on your car?
Yes ..I now have over 100,000 miles on my car (wiggle) I did alot of trips from NC to NY...So the answer would be NO. 998,857 > 100,000.

Cats usually last a little more than 100k. When they go bad, they decrease flow dramatically. You have a big drop in performance when that happens.
O2 sensors start going bad around 80k. Most likely it's the O2 sensor.