This is so crazy. I have a 2020 with only 36k miles and a Grimmspeed intake. I thought it couldn’t be a vacuum leak the car is still pretty relatively new for its mileage, it couldn’t be the 02 or MAF and when you rotated the filter and saw the numbers I was blown away. I immediately went and took out my filter and gave it a good clean and used another side and bam code cleared. For safety measures I went ahead and got a K&N filter for the quality. Thank you so much for this video. I was starting to stress but not no more. Gotta keep them filters clean!
Mechanic, I changed my spark plugs, lubed gasket on gas cap, cleaned and recharged air filter, cleaned MAF sensor with CRC MAF cleaner and put battery on a trickle charger to make sure fully charged, no obvious vac leak. Reset ECU and Light + Code came back after 10 miles. I have a Grimspeed intake setup that been on for over a year no issues.
Did you get it resolved? Look for exhaust leaks, also check fuel pressure, that's where I'm going next. Sometimes evap purge valve can be stuck open, If you can pinch off the line and things return to normal, that's your problem.
I did found the leak using break-clean all around my intake manifold. it was a purge solenoid valve tucked atop block in a rat nest of 1/4 tubing, took a second because tubing was aligned to broken nipple which didnt look like it was off the valve. @@crazyDIYguy
@@chrislehmann6240 I remember moving my front stock air/fuel sensor about 12 in downstream of the turbo. Excessive studying I found people said that's where you get the best reading, maybe screwing you up in other locations?.
I have the same issue on my woman’s 2018 WRX. But PO170 too rich… I have found another video that diagnoses it as the extension for the wiring harness getting corroded. I am going to install the iWire extension on it, and use dielectric grease on it. I hope that is problem.
I got a 2021 subaru wrx and it just threw this code today. Haven't had time to check it out but it's only got 31k miles so i'd be very suprised if my o2 sensor is bad. I have the same intake so i'll try this first and then check for vacuum leaks and clean the MAF. My car is on e85 too but I doubt its something related to that. Any advice for trying to fix this code?
Im having this problem, no specific code for it yet, but positive fuel trims at 35 when cruising. Very random and sporadic. I've been through the evap system, disconnected it temporarily and plugged it off. PCV system, temporarily plugged. Both O2 sensors, thoroughly checked for intake leaks, exhaust leaks. Spark plugs and coils, EGR solenoid deleted, nothing made it different. Next I am checking fuel pressure. This is very aggravating
@@subtledriver this one was a 2012 Subaru outback 6mt natural aspirated, it turned out to be a defective brand new upstream air/fuel sensor I just installed, known good was swapped and fuel trims were beautiful.
This is so crazy. I have a 2020 with only 36k miles and a Grimmspeed intake. I thought it couldn’t be a vacuum leak the car is still pretty relatively new for its mileage, it couldn’t be the 02 or MAF and when you rotated the filter and saw the numbers I was blown away. I immediately went and took out my filter and gave it a good clean and used another side and bam code cleared. For safety measures I went ahead and got a K&N filter for the quality. Thank you so much for this video. I was starting to stress but not no more. Gotta keep them filters clean!
The more videos like this I see, the better i feel about leaving my stock intake alone.
My Bugeye has more of a straight shot passed the MAF but the filter being shotty is great information.
Mechanic, I changed my spark plugs, lubed gasket on gas cap, cleaned and recharged air filter, cleaned MAF sensor with CRC MAF cleaner and put battery on a trickle charger to make sure fully charged, no obvious vac leak. Reset ECU and Light + Code came back after 10 miles. I have a Grimspeed intake setup that been on for over a year no issues.
Did you get it resolved? Look for exhaust leaks, also check fuel pressure, that's where I'm going next. Sometimes evap purge valve can be stuck open, If you can pinch off the line and things return to normal, that's your problem.
I did found the leak using break-clean all around my intake manifold. it was a purge solenoid valve tucked atop block in a rat nest of 1/4 tubing, took a second because tubing was aligned to broken nipple which didnt look like it was off the valve. @@crazyDIYguy
What engine/code/mods?
EJ257, P0171, high flow cat DP, grim CAI, cobb e-tune.
@@chrislehmann6240 I remember moving my front stock air/fuel sensor about 12 in downstream of the turbo. Excessive studying I found people said that's where you get the best reading, maybe screwing you up in other locations?.
I have the same issue on my woman’s 2018 WRX. But PO170 too rich… I have found another video that diagnoses it as the extension for the wiring harness getting corroded. I am going to install the iWire extension on it, and use dielectric grease on it. I hope that is problem.
Im happy i saw this video i have a cobb intake i bought the car used and got this code
Same I bought an 18 limited used and it came with stage 1. Im having issues with this code all the time.
@portland9548 I change the the intake to a K&N one and then the code went away
@@joshuaellington4583did you have to get a new tune?
Very interesting!!
I got a 2021 subaru wrx and it just threw this code today. Haven't had time to check it out but it's only got 31k miles so i'd be very suprised if my o2 sensor is bad. I have the same intake so i'll try this first and then check for vacuum leaks and clean the MAF. My car is on e85 too but I doubt its something related to that. Any advice for trying to fix this code?
Air fuel ratio sensor
Get a different intake, or clean maf and get a different cone filter from k&n or aem.
Im having this problem, no specific code for it yet, but positive fuel trims at 35 when cruising. Very random and sporadic. I've been through the evap system, disconnected it temporarily and plugged it off. PCV system, temporarily plugged. Both O2 sensors, thoroughly checked for intake leaks, exhaust leaks. Spark plugs and coils, EGR solenoid deleted, nothing made it different. Next I am checking fuel pressure. This is very aggravating
What vehicle?
@@subtledriver this one was a 2012 Subaru outback 6mt natural aspirated, it turned out to be a defective brand new upstream air/fuel sensor I just installed, known good was swapped and fuel trims were beautiful.
Glad I figured it out. Where did u get the new o2 sensor?
Spt intake ???
Not my favorite. Aem/k&n is ideal