PO328 code questions - Subaru Outback - Subaru Outback Forums
 
LinkBack Thread Tools Rate Thread
post #1 of 4 (permalink) Old 04-22-2012, 04:46 PM Thread Starter
Registered User
 
Join Date: Feb 2012
Posts: 5
Feedback Score: 0 reviews
PO328 code questions

Was given an 03 H6 sedan with 178,000 miles and a bunch of problems. All fixed except a PO328 code. I have reset multiple times, there is no rhyme or reason as to when the code comes back, once it came back instantly, once with three monitors reset and once with 7 reset. The CEL also shut off on its own one day then came back on the next with the same code.

This car has never had the plugs replaced, obviously its on my list of things to do, I also understand that the intake needs to be pulled to replace the knock sensors. Based on the experience of you guys do you think that the random times I get the code back could be a result of bad plugs causing it and that the knock sensors actually work?

Is there any benefit to doing the plugs on an H6 with the intake off? I am trying to limit what I spend on the car, if it needs both knock sensors and plugs I can do it but at this point I need to pass inspection and do so without draining my wallet anymore.

Any help or shared experiences would be greatly appreciated!
pullthehook150 is offline  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 04-22-2012, 06:27 PM
Registered User
 
Join Date: Jun 2006
Location: Eastern ON Canada
Car: 07 OBW 2.5i D-4AT
Posts: 9,731
Feedback Score: 5 reviews
With 178,000 miles on the original plugs, I wouldn't be surprised if there were some problems. However, the P0328 code isn't a knock problem code as might occur if a cylinder was malfunctioning; rather, it's a diagnostic code indicating an open circuit in the knock sensor electrical connection back to the ECU.

The knock sensor has a connector going to the main engine wiring harness -- the contacts there could be poor. Also, the metal body of the sensor itself is the ground for the sensor signal and it goes through the contact between the metal body of the sensor and the engine block, so this interface could also be problematic.

Not sure how much work it is to access the knock sensors on the H6 (perhaps others can fill in), but checking the connections might be all that's needed for that intermittent knock sensor CEL.
plain OM is offline  
post #3 of 4 (permalink) Old 05-20-2013, 09:07 AM
Registered User
 
Join Date: Aug 2012
Location: Grantsville, WV
Car: 01 outback 2.5, AT, jeep yj, xj
Posts: 21
Feedback Score: 0 reviews
I know this is an old thread, but to help others here, I wanna say that my 00 OBW, 2.5, was throwing a PO328, and after pulling other knock sensors and coil packs from engines here, I found the problem to be the spark plug gap. After narrowing the gap with a couple um... precision taps against the fenderwell, car runs great, and the CEL stays off. Don't throw money into parts you might not need.
crazycraig is offline  
post #4 of 4 (permalink) Old 05-20-2013, 05:52 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
Quote:
Originally Posted by crazycraig View Post
I know this is an old thread, but to help others here, I wanna say that my 00 OBW, 2.5, was throwing a PO328, and after pulling other knock sensors and coil packs from engines here, I found the problem to be the spark plug gap. After narrowing the gap with a couple um... precision taps against the fenderwell, car runs great, and the CEL stays off. Don't throw money into parts you might not need.
I have been saying that all along. Test it, test it, test it. Then replace.
cardoc 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