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Discussion Starter · #1 ·
Installed the HKS down pipe, and for added insurance, I installed the Poneyexpress fix, guess what get a cel and the code is P0139, has anyone else experienced this? could it be a bad part from pony express? has anyone not modified the sen sor and gotten away without a code?
 

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What CEL is that? If its this wild wild guess- catylytic converter malfunction- then the sensors may be picking up a different temperature reading than it is used to. If so, just an opinion- don't worry much as cats work via heat and they are all not created equal.
 

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I think you might actually have a bad O2 sensor.

Bank 1 Sensor 1 is a fuel trim sensor, not a catalyst monitoring one. Slow response means it did not start switching within a certian preset time frame the ECU looks for.
 

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Discussion Starter · #5 ·
I got it to set again and checked it, it is bank 1 sensor2, this would be the cat sensor correct? IO guess i need to call pony express tomorow. by the way, does anyone know another company that sells o2 simms?
 

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Yes, I believe sensor 2 is a catalyst monitor, but I do not have a Subaru manual handy. I know sensor 1 is always fuel trim. I would double check any connections, if you haven't already.
 

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Discussion Starter · #9 ·
I removed the silencer last week, no problems, this week I installed the HKS pipe along with the PE mod. I drove the car about 5 miles and the CEL came on P0139, I erased thecode and went for another ride and Poof the light came on again, same code. I will check the connections tomorrow, I did use standard connections and did not use soder. Any way I had the Casper 02 sims on mt 99 vette, and never had a problem. Seems strange that the code is for a slow moving sensor, and not the standard cat code. some times it sucks to be different!
 

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where exactly did you put that PE mod?

The Sensor in the uppipe is not an 02 sensor it is an EGT sensor. It is "fixed" with a 2 ohm resistor mod not a PE mod.

The PE mod is used ONLY if you have installed a turboback exhust or are running racepipe. This is the sensor right before the midpipe cat.

You never want to touch the O2 sensor in the manifold. This is responsible for your closed loop fuel control and should NEVER be tampered with.
 

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Discussion Starter · #11 ·
Well, I took a chance and removed the PE mod, and guess what, It now sets the P0420 code, i guess the PE was bad, Will call tomorrow to get it swiched out, thanks for all the help.
 
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