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Discussion Starter · #1 ·
So there are a lot of threads on this, and yes, I have read all of them. I keep getting this code very intermittently. It seems like it could be virtually anything, exhaust leak, fuel pump, injectors, o2 sensor, wiring harness, intake system.

I began getting this code immediately after a turbo install. The exhaust leak, I suspect, would have to be BEFORE the o2 sensor to throw this code right? So essentially it would have to be between my turbo and DP. I don't think there is a leak there though (and it's kind of hard to check for one too).

Who else has had this code, did it come back, and how did you fix it? I'm trying to get an idea of the most likely culprit.

The car has had no negative effects from this code, but it has come back 3 times now total. The car runs great, the fuel trims seem to be fine, WOT AFRs are right in line with where they should be. Any other ideas?
 

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I have this code and its driving me insane! My AFR is running rich so that might be why. At WOT its at 10.1

Now all I have to do is convince my tuner to fix and actually listen to me for once!
 

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[Local Team Member], aka JDAVID-EVO X
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got this code two days a go and I have no idea what to ccheck :/

My o2 sensor is dissable (I mess it up when I was replacing my dp) and first o2 sensor is giving me issues too :( WTH??.. Any help?? first time getting this code.
 

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Discussion Starter · #5 ·
got this code two days a go and I have no idea what to ccheck :/
I would check for a boost leak or anything that may screw up your intake system (look for issues near your maf, perhaps a busted coupler?) , or an exhaust leak first.

I have this code and its driving me insane! My AFR is running rich so that might be why. At WOT its at 10.1

Now all I have to do is convince my tuner to fix and actually listen to me for once!
I doubt this is the culprit. Stock evos run 10.1 or richer often and they don't have issues with this code.


My code was related to massive compressor surge (as far as I can tell, ever since I fixed that issue it hasn't come back in over a month now).
 

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I just got this code a few days ago. Checked for leaks and found nothing; I cleared it and it came back 2 days later.

Autozone's printout:
P0133 - Cylinder 1-4 heater oxygen (front) sensor circuit slow response
Probably cause:
-rich A/F ratio-fuel system fault
-open or short circuit condition
-Poor electrical connection
-faulty 1-4 O2 sensor

I ordered a new one and should be in next week, I'm just curious as to why it went out? Car has ~15k miles on it, I run a MAP downpipe + custom 3" aluminum straight exhaust (no cat, no muffler).

Any thoughts??
 

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Discussion Starter · #7 ·
I just got this code a few days ago. Checked for leaks and found nothing; I cleared it and it came back 2 days later.

Autozone's printout:
P0133 - Cylinder 1-4 heater oxygen (front) sensor circuit slow response
Probably cause:
-rich A/F ratio-fuel system fault
-open or short circuit condition
-Poor electrical connection
-faulty 1-4 O2 sensor

I ordered a new one and should be in next week, I'm just curious as to why it went out? Car has ~15k miles on it, I run a MAP downpipe + custom 3" aluminum straight exhaust (no cat, no muffler).

Any thoughts??
It's highly unlikely that it's the o2 sensor. Did you install the exhaust recently? Are you sure you don't have an exhaust leak?
 

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It's highly unlikely that it's the o2 sensor. Did you install the exhaust recently? Are you sure you don't have an exhaust leak?
I haven't been able to really look around the downpipe area, but I've been running this exhaust for almost a year and have had no problems. I will try a more in-depth search
 

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It's highly unlikely that it's the o2 sensor. Did you install the exhaust recently? Are you sure you don't have an exhaust leak?

You sir are correct. Took out the heat shields again today and after using a spray bottle I found a leak on my MAP downpipe. Now to get that sucker out and fixed. Thanks for the help!
 

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Still no other insight, ey? I'm thinking its because I have a MAP tubular header and a large AMS downpipe that causes the exhaust gasses to get to the sensor more slowly than they normally would. I'm thinking about welding a bung up closer on the downpipe to move the O2 closer. I notice that even my wideband O2 lags considerably. No wonder it has a hard time with STFT bouncing everywhere. I can't find any leaks or anyone else saying they found any other solutions.
 

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Still no other insight, ey? I'm thinking its because I have a MAP tubular header and a large AMS downpipe that causes the exhaust gasses to get to the sensor more slowly than they normally would. I'm thinking about welding a bung up closer on the downpipe to move the O2 closer. I notice that even my wideband O2 lags considerably. No wonder it has a hard time with STFT bouncing everywhere. I can't find any leaks or anyone else saying they found any other solutions.
I've got the MAP tubular mani and AMS downpipe as well and I too have the P0133 code. I just recently got the car and I was told the front O2 is a fairly new sensor. The code is coming back every other day after I clear it. I need to check for any exhaust leaks.
 

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2017 Audi RS3 Stage 2 Unitronic Tune 93 Octane
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I had this at first:
P0172 Bank 1 System too rich
P0133 Heated Oxygen Sensor Circuit Slow Response (Sensor 1)
P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

Then I was only left with P0133. I checked for exhaust leaks, changed the primary o2 sensor twice. Did a leak test, compression test, and found it was my tune was too rich. The temp had recently rose to 114 degrees highs. I was tuned at 72 degrees in So Cal.
 

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Bump,
Same code cant find any leaks in exhasut, or boost. Sometime it will come on 1/2 mile down the road afeter i clear it or it might stay off for 75 miles or so.

What is the deal? Almost to the point of going back stock and selling the car.

ETS intake, ETS TBE recirc Dp, grmimspeed EBC,
 

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I've had this code ever since I bought the car also and what I noticed on mine is once I clear the code it won't come back if I'm a 3k revs or above for example highway speeds but one I'm in slow stop an go traffic below 3k is when my light comes on and once it's on it seems to mess with my throttle response from time to time especially when it's a cold start does anyone else have any insight mods are
Id1000cc injectors
Agp intercooler and piping
Agp cold air intake
Kelford cams
Cobb ebc
Megan dp an test pipe
Greddy single exit
Tubular manifold
 

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Still no other insight, ey? I'm thinking its because I have a MAP tubular header and a large AMS downpipe that causes the exhaust gasses to get to the sensor more slowly than they normally would. I'm thinking about welding a bung up closer on the downpipe to move the O2 closer. I notice that even my wideband O2 lags considerably. No wonder it has a hard time with STFT bouncing everywhere. I can't find any leaks or anyone else saying they found any other solutions.
I've got the MAP tubular mani and AMS downpipe as well and I too have the P0133 code. I just recently got the car and I was told the front O2 is a fairly new sensor. The code is coming back every other day after I clear it. I need to check for any exhaust leaks.
I'm glad to not be alone! I still haven't done anything with it but I need to before inspection this year. Going to give MAP a shout for their opinion. My wideband confirms the response is actually slow because my WB gauge is clearly delayed by about a second when the car stumbles and then AFR swings very lean.
 
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