Code P0421 On 2001 Mitsubishi Galant! - Mitsubishi-Forums.com
 
LinkBack Thread Tools
post #1 of 6 (permalink) Old 10-16-2009, 01:12 PM Thread Starter
Newbie
 
Join Date: Oct 2009
Posts: 1
I own a 2001 Mitsubishi Galant ES 4 cyl 2.4l . I have a problem on the vehicle that truly bothers me:

Code P0420 and P0421. A year ago i had the same issue, had to change the O2 sensor after catalyst, this was done and an O.E. sensor was installed after catalyst. Also the O2 sensor before catalyst was changed but the new one is a Bosch (i recently heard bad things about those).

This being, i wanted to know what would be the course of action (I was going to purchase an O.E. sensor for BANK 1 SENSOR 1 to replace the Bosch that i have currently to see if it makes the codes go away since that particular sensor most likely went bad).

I want to thank you in advance for helping me out.

Regards!
hotsheets is offline  
Sponsored Links
Advertisement
 
post #2 of 6 (permalink) Old 10-16-2009, 03:26 PM
Super Moderator
 
KiT TeUnG 2549's Avatar
 
Join Date: May 2008
Location: Houston , Texas
Posts: 3,986
Send a message via Yahoo to KiT TeUnG 2549
Well the factory sensors are Nippondenso / Denso . This code can be caused by several things. It can also be caused by the sensor it self . One thing that can cause this code is an over aged catalytic converter , if the air flow thru the converter is too high of a rate it will not allow the pre catalytic HO2 sensor to heat up to the proper heat range as desired by the PCM when the engine is cold.

A crack in the exhaust manifold / exhaust header pipe , exhaust leak pre catalytic converter , will cause small amounts of air to bypass the HO2 sensor and cause it not to heat up quickly enough during cold start, warm up modes. And lastly the HO2S itself may be aged and bad and the heating element may not be working to its full range on warm up.

You Look Like I Need Another Drink
KiT TeUnG 2549 is offline  
post #3 of 6 (permalink) Old 07-16-2010, 08:27 PM
Newbie
 
Join Date: Sep 2007
Posts: 15
If your motor mounts are bad it can cause the engine to rock too much and pull on the flex pipe and let air out?
elkypro is offline  
post #4 of 6 (permalink) Old 07-16-2010, 11:33 PM
Super Moderator
 
KiT TeUnG 2549's Avatar
 
Join Date: May 2008
Location: Houston , Texas
Posts: 3,986
Send a message via Yahoo to KiT TeUnG 2549
If he has noticed an exhaust leak . But there would still be the proper amount of air passing over the aft cat sensor . it all depends , most models had the catalytic converter right after the exhaust manifold on this model so it would be less likely , but if it had the header style and the cat was under the body like older ones then maybe a little, but hed notice an exhaust leak

You Look Like I Need Another Drink
KiT TeUnG 2549 is offline  
post #5 of 6 (permalink) Old 07-22-2010, 02:25 PM
Newbie
 
draco528's Avatar
 
Join Date: Jul 2010
Location: troy, tx
Posts: 5
Send a message via Yahoo to draco528
i need a radio code for a 2002 mitsubishi Eclipse Spyder GT....

MR490088
15165228D

i can't find no one who know's...
draco528 is offline  
post #6 of 6 (permalink) Old 07-23-2010, 08:10 AM
Veteran
 
SRSONE's Avatar
 
Join Date: Jun 2008
Location: naples,fl
Posts: 4,032
there is a post for radio codes....

this post is about p0420 codes which are engine codes..

dont thread jack.....

I am a rocker, I am a roller, I am an out of controller!
the nightrider


What the **** is an aluminum falcon?
SRSONE is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mitsubishi-Forums.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome