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Brand new front o2 bad after rebuild?


zero260

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I need confirmation on what I'm thinking. I but a new front o2 sensor in after I rebuilt my motor and have driven about 300 miles. I just flashed my ECU to correct a few things and got a P0134 almost immediately after flashing. I logged a drive around my neighborhood and it was 14.7 the entire time. I also noticed when I was logging previously it read 14.7 the entire time. Did I get a faulty o2 sensor out of the box? it's a Denso unit, not bought OEM, but Denso makes the OEM units.

romraiderlog_20160725_195512.csv

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Certainly seems odd - that code is not listed as a normal Subaru Code - but seems to be a generic Code for "No Sensor Activity"

 

Personally - to me it would seem like the plug or wiring is either cut/broken or maybe just disconnected? Or better yet did you code out the 02 sensor in the tune and that's not set correctly?

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Did you install the O2 sensor (A/F ratio sensor) before you installed the motor or after the motor was in?

 

#1 issue when installing a motor is people install the O2 sensor before. The problem here is, the O2 sensor sticks out far enough that it bangs against the sub frame in the engine well when aligning the motor up to the trans. All it takes is a few bangs and the O2 is damaged. If this is the case, you will need to buy a new O2 sensor. I'm guilty of doing this too, lesson learned.

My wife's balls are delicious.
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Well, i changed the o2 sensor or under warranty and for the same code. My current tune has cel code p0031 shut off to eliminate my cel. I went back to stock tune and only p0031 comes on. But on my custom tune the p0134 comes on. So I adjusted my tune to allow p0031 to through a code and it doesn't throw p0134 anymore. But my logger still only records 14.7 on my front o2. Anyone have any ideas on that?
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I had one today that just pegged 15.5 no matter what. Replaced with a new Denso and worked great. I think if you are getting static values, either the sensor is no good or there's a problem with wiring.

 

The code we were getting was an upstream o2 low circuit code. Can verify actual code later.

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So I started diagnostic per the FSM, didn't have any voltage at the harness, Found a fuse marked SBF-5 to be burnt out, replaced it and now its working perfectly

 

 

Great to hear you know how to use the tables Good Job.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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