Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

Sensor-tive issues, o2 and knock sensors


  • Please log in to reply
3 replies to this topic

#1 VinnyVinnVinn

VinnyVinnVinn

    Newbie

  • Members
  • Pip
  • 4 posts
  • Santa Cruz California

Posted 23 January 2014 - 06:57 PM

Hi everyone, I just accquired a 2000 Subaru Legacy Brighton and I am having a few issues with it.  The check engine light is on and when I pulled the codes I came up with P0325 Knock Sensor no. 1 Circuit malfunction P0420 Catalyst Efficiency Below Threshold and P0133 02 Sensor Slow Response.  I am assuming that the two sensor related problems would trigger a P0420 so I should resolve these first.  What I wanted to know is if there is a difference between the various replacement sensors.  In otherwords, should I buy straight from the dealer or will a Bosch sensor from autozone or napa be good enough?  Also, is the slow response from the o2 sensor caused by a faulty sensor, or could it be caused by something else like a loose wire or bad connection or improper fuel trim etc?  Thanks, I look forward to your help and answers and I assure you, I will probably have many more questions.



#2 Fairtax4me

Fairtax4me

    Su bah roo'n

  • Gold Subscribers
  • 7,897 posts
  • Charlottesburg, VA

Posted 23 January 2014 - 08:13 PM

A lot of people use knock sensors from EBay/Amazon with good results.

O2 sensor slow response is usually the sensor (happens when they get old), but it can be caused by other problems.

Bosch O2 sensors will work fine. Do not get the universal fit type. Check the shape of the connector on your sensor (check carefully because some differences are minor), and compare to new sensors before you order.

There are two or three different sensors that your car could have, and they work slightly differently than one another. Getting the wrong type of sensor will lead to more (worse) problems.

#3 VinnyVinnVinn

VinnyVinnVinn

    Newbie

  • Members
  • Pip
  • 4 posts
  • Santa Cruz California

Posted 23 January 2014 - 11:51 PM

Thank you Fairtax4me, just curious but what is the difference between the different sensors, how do I tell them apart?



#4 Fairtax4me

Fairtax4me

    Su bah roo'n

  • Gold Subscribers
  • 7,897 posts
  • Charlottesburg, VA

Posted 24 January 2014 - 12:18 AM

Internal differences mostly. Some have to have a reference voltage from the ECU, which affects the output of the sensor. And of those there are 3 or 4 different designs which all use different reference voltages. Others create the voltage in the sensor. The outer cases can be slightly different, but not different enough to tell them apart unless you're the engineer that designed the sensor. The fun part is that just about all of them have 4 wires! So there's really no way to tell unless you KNOW which one you need.

Pay close attention to the plug, because that's how the manufacturer keeps you from plugging in the wrong one.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users