RacinMylancer

iTrader: (7)

Can anyone help me?

Plugged an OBD II scanner in today and found out my CEL is on because of "P0421" "Warm Up Catalyst Below Threshhold"...

I don't have a service manual and I don't know what the warm up catalyst is. Feel free to call me an idiot, and tell me I know nothing about my car, but after doing so, please give me some advice. Is this something I can fix on my own? Can a "generic" shop take care of this for me? Do I need to go to Mitsubishi (please, please, don't tell me that...)?

Any help will be appreciated and probably reciprocated, if you live around me. Feel free to AIM me or give me a call or whatever. Cell's 714.716.6102. Name's Scott.

Thanks

blaze_125

iTrader: (8)

Did you change your header?

RacinMylancer

iTrader: (7)

nope. only mods are breather mods... short ram intake and exhaust. stock headers intact. i don't think the aftermarket header guys were getting the same error code anyway...

RacinMylancer

iTrader: (7)

bump... help please?

psy-q

iTrader: (1)

testpipe/cat delete? That error code is to tell you that its getting a funny reading at the 2nd O2 sensor.

RacinMylancer

iTrader: (7)

none of the above. 2nd cat is gone, but the 2nd o2 sensor is behind the first cat and before the 2nd, so that can't be the issue.

any other input?

Delshay

did you ever find out what happened?

03OZLancer

I got a test pipe and I don't a CEL. Are you sure the O2 sensor and ECU harness are all plugged together tightly? Could your first cat be cloged?

jaymz916

Yes it is, that's the one I got after the header install.

RacinMylancer

iTrader: (7)

k, got it figured out; exhaust manifold was bad (cracked, whatever... service manager didn't tell me, cuz his tech didn't tell him), but they're putting a new on one under warranty, so i'm not stressin'.