[emsoledan]

Noob here! I've had my 2015 VA STi for almost a year now and I've had the spark plugs replaced last October in a shop since I've had my first CEL. It drove nicely for a day but it started having CEL again after a week. I went back to the shop and apparently the mechanics forgot to plug in my Secondary Air Injection System, I got the P0410 code. It went on to drive okay for the next few months but I frequently get an error stating that the system's too rich; the P0172 code a lot. The mechanics suggested that it was just the MAF sensor getting dirty and advised me to just clean it. It has been running rich a lot since I replaced its spark plugs in the shop. They used Laser Iridium Premium NGK spark plugs. Is it possible that the reason was I was running with the Secondary Air Injection System plugged off? The mechanics told me it was nothing but I seem to suspect their skills. Any advices for this or other threads which may have the answer for my problem? Starting to think that the only solution is a tune. Thanks!

 

[yamahaSHO]

I'd start with a boost leak test and verify the fuel pressure regulator has its reference line connected.

Tunes do not fix mechanical problems and tune issues so not creep up out of nowhere when all has been fine prior.

 

[WaltSTi19]

I've been dealing with that damn P0172 the past few days. I've cleaned the MAF sensor with MAF sensor cleaning fluid, I've reflashed the ecu with my AP, and ended up taking it to the dealership. They told me that the issue seems to be something with the actual tune (I have an OTS one, running on stage 2). I may go ahead and just do an e-tune, which I'm being told it should fix the issue. I had to take a break from my STI today and drove my FRS instead lol.

 

[emsoledan]

I've been dealing with that damn P0172 the past few days. I've cleaned the MAF sensor with MAF sensor cleaning fluid, I've reflashed the ecu with my AP, and ended up taking it to the dealership. They told me that the issue seems to be something with the actual tune (I have an OTS one, running on stage 2). I may go ahead and just do an e-tune, which I'm being told it should fix the issue. I had to take a break from my STI today and drove my FRS instead lol.

damn, STIs be really complicated huh? haha got mine fixed today. brought it to a subaru specialist and apparently, the other shop that replaced the spark plugs did not gap them properly. turns out only one spark plug was working properly and the rest were clean as hell. the specialist shop just re-gapped and cleaned it, so far it fixed my issue regarding the P0172. hopefully it doesn't run rich again. the last time it ran rich and i didn't have any tools with me, i just disconnected the battery and as to my surprise it started working perfectly again lol.

 

[yamahaSHO]

I've been dealing with that damn P0172 the past few days. I've cleaned the MAF sensor with MAF sensor cleaning fluid, I've reflashed the ecu with my AP, and ended up taking it to the dealership. They told me that the issue seems to be something with the actual tune (I have an OTS one, running on stage 2). I may go ahead and just do an e-tune, which I'm being told it should fix the issue. I had to take a break from my STI today and drove my FRS instead lol.

A tuner will require you fix your mechanical issue first.