p0174 and p0420 - Subaru Outback - Subaru Outback Forums
 
LinkBack Thread Tools Rate Thread
post #1 of 8 (permalink) Old 02-13-2013, 02:42 AM Thread Starter
Registered User
 
Join Date: Jan 2012
Posts: 4
Feedback Score: 0 reviews
p0174 and p0420

new cat and new 02 sensors and no they are after market, i have a snap modis so i watched the 02 sensors going down the road and there they were acting fine none were sticking on high or low they read 127.991 ma then -127.91 ma , they jumped high low and never stuck on either one, by the time my ride came to a end there was two codes pending p0174 and p0420, i can not get the engine light to stay off, and please dont tell me you cannot us aftermarket parts because everone else in the world uses aftermarket parts.
mikeymoby is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 02-14-2013, 12:20 AM
Super Moderator
 
AWDFTW's Avatar
 
Join Date: May 2007
Location: About to leave Chicago!
Car: 2003 2.5 4EAT with AWP.
Posts: 7,994
Feedback Score: 0 reviews
Thread moved to correct forum.

2003 Outback wagon: "Kaylee". 144,000 and counting.
Basics: Quaker State Ultimate Durability 5W30, PureOne oil filter, Fram air filter, Valvoline Maxlife Dex/Merc ATF, Mobil 1 75W90, Michelin Primacy MXV4.
Mods: 2004 Forester XT shift knob, Fumoto oil drain valve, Phillips VisionPlus low beams, Phillips HIR1 high beam upgrade, Nokya Hyper Yellow 2500K fog lights.

Also: More rust than I care to think about.
AWDFTW is online now  
post #3 of 8 (permalink) Old 02-14-2013, 12:22 AM
Super Moderator
 
AWDFTW's Avatar
 
Join Date: May 2007
Location: About to leave Chicago!
Car: 2003 2.5 4EAT with AWP.
Posts: 7,994
Feedback Score: 0 reviews
Furthermore, let's have some actual details please?

Vehicle?
Miles?
Known service history?

Why did you replace the cat? They rarely fail.

And I hate to tell you....but aftermarket cats and O2 sensors....typically are not gonna last long or work right on these cars.

2003 Outback wagon: "Kaylee". 144,000 and counting.
Basics: Quaker State Ultimate Durability 5W30, PureOne oil filter, Fram air filter, Valvoline Maxlife Dex/Merc ATF, Mobil 1 75W90, Michelin Primacy MXV4.
Mods: 2004 Forester XT shift knob, Fumoto oil drain valve, Phillips VisionPlus low beams, Phillips HIR1 high beam upgrade, Nokya Hyper Yellow 2500K fog lights.

Also: More rust than I care to think about.
AWDFTW is online now  
post #4 of 8 (permalink) Old 02-15-2013, 06:37 AM Thread Starter
Registered User
 
Join Date: Jan 2012
Posts: 4
Feedback Score: 0 reviews
it is a 2004 outback with a 2.5l 4cyl last year the check engine light came on and said the cat was bad, replace cat and both o2 sensors, 120000 miles no exhaust leak and o2 sensor go high low they switch back and forth like thay should. that makes no sense about after market not working if the computer is that senceitive then one little hicup wil turn the light on.
mikeymoby is offline  
post #5 of 8 (permalink) Old 02-15-2013, 09:56 PM
Moderator
 
cardoc's Avatar
 
Join Date: Aug 2012
Location: Austin, Texas
Car: 2001 VDC/SC One of a Kind
Posts: 10,420
Feedback Score: 2 reviews
One, you are looking at the incorrect sensor data. You need to look at the AF sensor Lambda data. That is what the ECM uses to determine rich or lean conditions.

Two, the sensor is reporting too lean, so looking at the Lambda data will give you an indication based on the voltage output of the sensor. If you are unsure of the sensor function, you can force a rich condition simply by spraying in an accelerant into the intake while its running and watch for the voltage to drop. If you used a "universal" sensor, that may be the issue.

Three, things that make an engine run lean and cause a P0174 or a P0420 are fuel delivery, vacuum leaks or incorrect AF, MAP or MAF data.

So, what you need to do is watch the correct data stream from the AF sensor and LTFT calculations. The ma values you are watching is the STFT waveform data. Check the fuel delivery. Check for vacuum leaks. and varify your air flow to be correct.

For now, ignore the P0420 and concentrate on the AF and fuel trim.

And read through here: http://www.subaruoutback.org/forums/...0420-diag.html
cardoc is offline  
post #6 of 8 (permalink) Old 02-17-2013, 04:12 PM Thread Starter
Registered User
 
Join Date: Jan 2012
Posts: 4
Feedback Score: 0 reviews
cardoc thank you thats what i was looking for good info on my proplem i needed to now i was looking at the wrong thing, it not like a gm were it is what it is, ford sometimes can be hard to find there proplems so thanks again i will checkout the things you were talking about, i have a modies from snapon, so i hopefully can figure it out.
mikeymoby is offline  
post #7 of 8 (permalink) Old 02-17-2013, 07:37 PM
Moderator
 
cardoc's Avatar
 
Join Date: Aug 2012
Location: Austin, Texas
Car: 2001 VDC/SC One of a Kind
Posts: 10,420
Feedback Score: 2 reviews
That Modis is a slow transfer rate, so if you force a condition, wait for the data from the scanner to catch up.
cardoc is offline  
post #8 of 8 (permalink) Old 03-12-2013, 07:08 PM Thread Starter
Registered User
 
Join Date: Jan 2012
Posts: 4
Feedback Score: 0 reviews
bad tps

the tps starts out at 16.9 % will that make for the two codes and yes the transfer rate is real slow
mikeymoby is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Subaru Outback - Subaru Outback Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

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.



User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Rate This Thread
Rate This Thread:



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