PO421:Warm Up Catalyst-below threshold (bank #1) CEL - evolutionm.net



Lancer Troubleshooting Get help with any troubleshooting problems you may have.

PO421:Warm Up Catalyst-below threshold (bank #1) CEL

Reply
 
 
 
Thread Tools Search this Thread
Old Dec 1, 2007, 08:53 PM   #1
Evolved Member
Thread Starter
iTrader: (10)
 
SLVROZ_03's Avatar
 
Join Date: Mar 2005
Location: Greenville, SC
Posts: 4,796
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: '03 OZ Rally

PO421:Warm Up Catalyst-below threshold (bank #1) CEL

So I searched and came up with only 2 threads with the mention of the PO421...honestly surprised!

What's interesting is that in both the threads both owners had an aftermarket header, so the reason for their CEL would be obvious (no 1st cat). But minus my Greddy EvoII canister, my exhaust system is stock.

Assuming bank #1 meant the first O2 sensor, does "below threshold" mean that the sensor isn't (all of a sudden) getting proper readings from the ecu? or proper readings from the exhaust gases (bad O2)?

I've not done anything to the car lately, and the CEL showed up while cruising down the road...nothing out of the ordinary. Guessing "Stewart" didn't like the fact the wife and I were test driving other cars today!

I had also read that a 2nd generation Eclipse O2 sensor is a direct match to ours? If I remember from the post, it was Alchemist that said that...so I can believe there's truth behind it. But has anyone ever used one?
*Edited for correction and quote :
Quote:
Originally Posted by WADADLIG_OZ View Post
I researched the Mirage forums and found that we share O2 sensors with a 1998 Eclipse turbo 2wd.

I have mine here that I need to install but when I checked it with looking at the one in the car it seems to be the same.

WADAD
Thanks ahead of time for your help and assistance!

Last edited by SLVROZ_03; Dec 1, 2007 at 08:58 PM.
Offline
 
Reply With Quote
Old Dec 1, 2007, 10:30 PM   #2
Evolving Member
iTrader: (43)
 
KcEvil8's Avatar
 
Join Date: Jan 2006
Location: chi-town
Posts: 112
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 2008 Mitsubishi Evolution X

your cat is bad. the ECU look at the O2 sensor before and after the cat to determine the efficiency of the cat. if the 2 O2 sensors data is very close for certain amount of time, the ECU will kick on the check engine light. that why people that have aftermarket exhaust manifold will have the code cause i think the cat is part of the exhaust manifold. bank 1 mean the bank of cylinders where the number 1 cylinder is and 4 cylinders car only have one bank.
Offline
 
Reply With Quote
Old Dec 2, 2007, 02:35 PM   #3
Evolved Member
iTrader: (19)
 
02-Lancer-Es's Avatar
 
Join Date: Aug 2006
Location: San Antonio
Posts: 2,394
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Turbo Lancer Es

dam i just got this code yesterday too!!
Offline
 
Reply With Quote
Old Dec 2, 2007, 06:47 PM   #4
Evolved Member
Thread Starter
iTrader: (10)
 
SLVROZ_03's Avatar
 
Join Date: Mar 2005
Location: Greenville, SC
Posts: 4,796
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: '03 OZ Rally

Were you out test driving other cars too? LOL I think "Stewart" overheard us and decided to be nasty.
Offline
 
Reply With Quote
Old Dec 2, 2007, 07:23 PM   #5
Evolved Member
iTrader: (19)
 
02-Lancer-Es's Avatar
 
Join Date: Aug 2006
Location: San Antonio
Posts: 2,394
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Turbo Lancer Es

lol nope im only 18 (just turned) and still go to HS so i dont have the cash
but ill prob just fix it
if its the converter its only 130 for one on ebay (obx high flow,bolt on)
but i hope i fixed it by doing a couple things earlier
Offline
 
Reply With Quote
Old Dec 2, 2007, 08:17 PM   #6
Newbie
iTrader: (4)
 
Redlancer's Avatar
 
Join Date: Sep 2003
Location: Quebec, Canada
Posts: 88
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 2003 Lancer ES Red

Smile

Quote:
Originally Posted by SLVROZ_03 View Post
So I searched and came up with only 2 threads with the mention of the PO421...honestly surprised!

What's interesting is that in both the threads both owners had an aftermarket header, so the reason for their CEL would be obvious (no 1st cat). But minus my Greddy EvoII canister, my exhaust system is stock.

Assuming bank #1 meant the first O2 sensor, does "below threshold" mean that the sensor isn't (all of a sudden) getting proper readings from the ecu? or proper readings from the exhaust gases (bad O2)?

I've not done anything to the car lately, and the CEL showed up while cruising down the road...nothing out of the ordinary. Guessing "Stewart" didn't like the fact the wife and I were test driving other cars today!

I had also read that a 2nd generation Eclipse O2 sensor is a direct match to ours? If I remember from the post, it was Alchemist that said that...so I can believe there's truth behind it. But has anyone ever used one?
*Edited for correction and quote :

Thanks ahead of time for your help and assistance!
How many miles you got on your car? I change my second 02 at 80 000 miles... A O2 sensors worn out with the time and milage, I'll change the sensors before the cat. (That work good on my car...)

A good read about Oxygen sensors...

http://www.ngksparkplugs.com/tech_su...x.asp?mode=nml
Offline
 
Reply With Quote
Old Dec 3, 2007, 02:19 PM   #7
Evolved Member
Thread Starter
iTrader: (10)
 
SLVROZ_03's Avatar
 
Join Date: Mar 2005
Location: Greenville, SC
Posts: 4,796
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: '03 OZ Rally

I've got 85k miles, so I know an O2 replacement was coming up on the things-to-do list...but it's always at the most inconvenient times!
Offline
 
Reply With Quote
Old Dec 3, 2007, 05:22 PM   #8
Newbie
iTrader: (4)
 
Redlancer's Avatar
 
Join Date: Sep 2003
Location: Quebec, Canada
Posts: 88
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 2003 Lancer ES Red

I bougth mine from this compagnie:

http://www.automedicsupply.com/

Good pprice and fast shipping. They work great too.

(Don't buy the universal one... They don't come with the plug.)

Last edited by Redlancer; Dec 3, 2007 at 05:25 PM.
Offline
 
Reply With Quote
Old Dec 3, 2007, 05:26 PM   #9
Evolved Member
iTrader: (9)
 
atilla's Avatar
 
Join Date: Jun 2006
Location: NH
Posts: 1,240
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 02 OZ

if you are using the stock header and you don't have a lot of cash i have my stock header with a working cat that i could send your way for a few bucks.

alternatively you can do the non-fouler trick on the 2nd O2 sensor for maybe five bucks and fifteen minutes of your time and that CEL will disappear.
Offline
 
Reply With Quote
Old Dec 3, 2007, 05:38 PM   #10
Newbie
iTrader: (4)
 
Redlancer's Avatar
 
Join Date: Sep 2003
Location: Quebec, Canada
Posts: 88
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: 2003 Lancer ES Red

Quote:
Originally Posted by atilla View Post
if you are using the stock header and you don't have a lot of cash i have my stock header with a working cat that i could send your way for a few bucks.

alternatively you can do the non-fouler trick on the 2nd O2 sensor for maybe five bucks and fifteen minutes of your time and that CEL will disappear.
If the second O2 sensors is dead, the trick of the non-fouler will not work.

At 85 000 miles, I'm sure the O2 sensors is dead. (Like I have on my car.... Everything was fine and one day, bang the cel for the P0421.)
Offline
 
Reply With Quote
Old Dec 3, 2007, 05:40 PM   #11
Evolved Member
Thread Starter
iTrader: (10)
 
SLVROZ_03's Avatar
 
Join Date: Mar 2005
Location: Greenville, SC
Posts: 4,796
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: '03 OZ Rally

So with it saying bank #1, doesn't that mean the first O2 sensor though?
Offline
 
Reply With Quote
Old Dec 3, 2007, 05:55 PM   #12
Evolved Member
iTrader: (19)
 
02-Lancer-Es's Avatar
 
Join Date: Aug 2006
Location: San Antonio
Posts: 2,394
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Turbo Lancer Es

i got my code cleared 2 days ago and it hasnt came back!!
i think it was because my spark plug wire was really loose!
Offline
 
Reply With Quote
Old Dec 3, 2007, 06:32 PM   #13
Evolved Member
Thread Starter
iTrader: (10)
 
SLVROZ_03's Avatar
 
Join Date: Mar 2005
Location: Greenville, SC
Posts: 4,796
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: '03 OZ Rally

How'd you clear it? Disconnect the battery?
Offline
 
Reply With Quote
Old Dec 3, 2007, 06:34 PM   #14
Evolved Member
iTrader: (19)
 
02-Lancer-Es's Avatar
 
Join Date: Aug 2006
Location: San Antonio
Posts: 2,394
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: Turbo Lancer Es

nope when u take it to autozone they clear it if u ask them without resetting everything (stereo ,clock)
or you can also reset it by disconnecting the battery for 5 mins!
Offline
 
Reply With Quote
Old Dec 4, 2007, 01:09 PM   #15
Evolved Member
Thread Starter
iTrader: (10)
 
SLVROZ_03's Avatar
 
Join Date: Mar 2005
Location: Greenville, SC
Posts: 4,796
Thanks: 0
Thanked 0 Times in 0 Posts

Drives: '03 OZ Rally

Well dang! The guy never asked while I was there...and it wasn't like they're busy either. I was their only customer! LOL I probably end up disconnecting the battery anyways...it has been a while and fuel has been dipping a little low lately.

Thx
Offline
 
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Po421 code!!! =[ barbiebxtch Lancer Troubleshooting 20 Mar 8, 2011 08:12 PM
P0420 Code After Exhaust? d3r3k Evo X Engine / Turbo / Drivetrain 5 Jun 30, 2010 11:25 PM
hmm..code p4021 Prejerism Lancer Engine Tech 12 Mar 23, 2010 09:08 AM
PO421:Warm Up Catalyst-below threshold (bank #1) CEL js0102 Lancer Troubleshooting 4 Jun 19, 2009 03:19 PM
Cel P0421 Nevaeh Lancer Troubleshooting 1 Jun 6, 2006 11:11 AM


Tags
01, bank, cat, catalyst, catalytic, check, converter, efficiency, engine, lancer, light, mitsubishi, p0421, po421, threshold, warm, warming, warmup

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off



All times are GMT -7. The time now is 05:24 PM.